He has (depending on your POV) been involved in a lot of scandals or been hit by a lot of smear campaigns. To name a few (and in the interest of fairness the good faith counter argument I have heard):

• He flew in the Helicopter of politically powerful Imam. This could have been considered quid pro quo and resulted in a 500 dollar fine from out ethics committee. However the Imam and the Trudeau family have been known family friends for a long time, so it is arguably a friendly visit not a work visit.
• He chooses the Governor general, a mostly ceremonial role. He choose the astronaut Julie Payette who was fired/resigned due to workplace harassment and creating a toxic work environment.
• Elbow gate: Trudeau (clearly accidentally) elbowed a female NDP member, the conservatives claimed that this was assault (this was during the height of the #metoo stuff) and that trudeau should step down, the NDP leader sided with the Conservatives and ultimately resigned from this debacle. I include this to mostly illustrate how aggressive the CPC have been at attacking his character.
• Jaspal Atwal is an indo Canadian who tried to assassinate an Indian politician. Trudeau then invited him to an indian diplomatic dinner. Atwal is a prominent business person with familial ties with Trudeau.
• the SNC lavelin affair. SNC lavelin is one of the largest construction companies in Quebec that did some super corrupt stuff, the CEOs went to prison, and the company was slated for to be dissolved. This would cost 1000’s of jobs, particularly in Trudeaus home riding. There is a special piece of legislation called a deferred prosecution agreement (DPA) passed by trudeau a few years earlier. This agreement would lessen the penalties on the company itself (not the CEOs) and allow the company to stay open. Trudeau spoke to his Minister of Justice, and allegedly put inappropriate pressure to go the DPA route, after which the minister resigned. Some believe that the minister resigning was a political play for her personal gain, others also argue that the pressure exerted by Trudeau was not wholely inappropriate. The DPA deal never happened.
• We Charity: A federal contract was made with the WE charity fro covid support. Turns out that WE had paid about half a million to Trudeaus wife to do a speech, despite both trudeau and WE signing documents stating they have no financial relationship. This created the appearance of Quid pro quo. Trudeaus finance minister was also found to have undisclosed financial ties which eventually lead to his resignation. Trudeau also prorogued parliament (essentially went on break) part way through the scandals investigation, a move that he heavily criticized the previous government for doing, however the prorogation also made sense to do for reaasons outside the scandal (the early days of the pandemic mainly). Trudeau proponents argue that Trudeau was not directly involved in the decision making and that WE was the only charity that was really a serious option for this program. The final ethics report on the subject found no wrong doing on Trudeaus part and the speech did not represent a conflict of interest, but that the finance minister had broken 3 conflict of interest laws. This finding happened long after the public eye had moved on.
• Brownface. It was uncovered that Trudeau dressed up in brown face on 2 separate occasions in 2001 for Halloween when he was a teacher and at least once in blackface. Francophone culture doesn’t have the same views on blackface as English culture, with minstrel shows being popular as far as 2012.

That’s what Trudeau has done scandal wise, in my experience this is what more conservative folks dislike about him. In my personal opinion there is nothing particularly out of the ordinary here and as someone whose wife is desi I can say the brown community largely seems to not care much about the brownface or Indian political scandals., but of course I only have that one community to look at.

He has some pretty controversial policies as well:

• A campaign promise of his first election was that “this would be the last election with FPTP”. While he raised a bill in Committee, it died there as conservatives didn’t want to change anything and the progressive parties could not agree on a particular system. Trudeau still had the option of ramming it through with his majority, but claimed that it would be damaging to pass it unilaterally without any other parties support. This is the single largest thing I see him get criticized for online, but I don’t see much about it IRL or in mainstream media.
• He made a big deal of appointing a cabinet that was 50% men and women. Some see it as pandering, some see it as misandry.
• The carbon tax implemented is criticized by the right for being too severe and the left for being too soft.
• He spent an awful lot of government money buying out oil pipelines that were held up by protests. Federal police also beat the shit out of those oil protesters.
• I don’t think any politician is beyond criticism over the handling of the pandemic, I don’t want to get into it too much but the raising cost of living and shutdowns do not bode well for the status quo government.
• He called an election in the middle of the pandemic (end of 2022) when he was ahead in the polls he ended up staying in almost the exact same minority government. This is traditionally a very unpopular thing for the government to do (elections are seen as expensive and annoying) and it was doubly so because of the pandemic.
• Trudeau has let in record levels of immigrants and refugees, while this has always been unpopular for right wingers it has become increasingly unpopular among progressives (largely due to the housing crisis, see below).
• Trudeau has been largely ineffectual at dealing with the housing crisis, late to admit there was a problem and getting criticism from both home owners and renters.
• Trudeau made a promise to provide all native communities with safe drinking water. He still has not done so, although he has closed more drinking advisories than were open when he was elected (more opened during the years).

In addition there’s also plenty of verifiably fake news and right wing craziness. Stuff like he’s a pedo who got fired from teaching or anything to do with the anti-covid protests.

I tried to make this fair, but obviously personal bias is unavoidable. I’m an ABC (anything but Conservative) voter who aligns most closely with the green party, probably much more pro-trudeau than most internet takes though. I’ve voted for LPC 3 times and will probably vote green in the next one.

My personal opinion is that while he is slow he is slowly sending things in the right direction so long as the NDP remain a minority. I think most of the negativity comes form the fact he’s been in power a long time and that the world has on the whole gotten worse. I hope he wins the next election because realistically the only other choice is a right wing populist. I don’t think it is possible for him to step down and keep the party in power, I somewhat suspect that the LPC is resigned to losing the next election and using that as a way to change out Trudeau.