has been losing a lot of votes since Sarah Wagenknecht went crazy.

Sorry, but Sarah did not go crazy. The new leadership of the party basically threw every pro-worker position over board and replaced it with liberal idpol bullshit in a cheap attempt to become the next Grüne/Bündnis 90. This predictably failed, because the orginal already exists and people at the existence minimum tend to be kind apathetic (at best) towards idpol. The massive loss of votes happened before Sarah said anything. She then correctly pointed outt he mistakes of the party leadership, which ignored her (at best, demonization was more common), which led to a continuation of the downwards trend.

I hope the party splits soon, those radlibs in the current Linke ruined it.