I totally disagree. Republicans are actively seeking his endorsement. Trump is choosing which candidates will run in which races. He is actively campaigning against all Republicans who voted to impeach him or convict him. And he is sitting on an $80 million dollars political war chest.
The only reason why he is silent on social media is because he has been banned from Twitter, Facebook and YouTube. Instead he has been releasing daily press releases.
Trump has been a busy boy. He is in no way fading into irrelevance as you claim.