I agree it is tyrannical. I also agree the intention is to choose the GOP nominee. But the Democrat track record is to BACK Trump nominees in the primaries, and it worked quite well in 2022. So they are going with that playbook here, making Trump a martyr and basically assuring he will be the nominee in 2024. It is pretty obvious this is the strategy, since they do nothing but attack "MAGA Republicans" at every turn, trying to put a wedge in the GOP.
If they were trying to imprison Trump and get him off the playing board, they would have indicted him before now. Indicting him now keeps everything alive before the election, since there will be motions and appeals ad nauseum, and Trump will not be tried until after the 2024 election, if at all. I think it is pretty likely these charges will be thrown out by a federal appeals court eventually.
This could backfire on them, or maybe it won't. But I have no doubt they want Trump to be the GOP nominee because running against him is by far the best strategy they have.