24.04 to 26.04 is a big version jump and sadly they can’t check every combination of hardware and software. Some people don’t go through the upgrade process and just back up their user data and reinstall when they want to upgrade to a new major release. In my experience, the automatic upgrader is usually fine but occasionally requires me to tweak something on my system.
Missing Nvidia drivers
Ubuntu has a “driver manager” software in the settings which should allow you to install recommended drivers.
Python not compatible with software like Proton VPN
What version are you using and how did you install it? You might be using an older version of their app and the issues are fixed in the latest versions. If you really can’t get their app to work, you can go to https://account.protonvpn.com/downloads#openvpn-configuration-files and download an OpenVPN file which you can import in your network settings. It doesn’t have all the bells and whistles as their app, but it still allows you to VPN your traffic.
My pc is not welcome in the new Ubuntu world :’(
I mean, isn’t Windows notorious for breaking things after an update as well? :P Computers in general are brittle and don’t handle change well.

























I’d like to suggest Linux Mint: It allows you to use guides and software written for Ubuntu but disables all the scummy stuff.