I think MTG was threatened with being 'primaried' and I'm assuming there is a viable MAGA loyalist candidate. After all, her district is rural Georgia so I assume heavily MAGA. SCROTUS took a large majority of the votes in 2016 71%, 2020 68%, 2024 68% vs the Dem candidates. She knew she couldn't win if the GOP primaries her at SCROTUS' behest. I can't remember where I read it, but somewhere she stated that IF she were to seek office again she'd run as an Independent.
I think what she sees (please, God!) is a Blue Wave at the midterms. Some pundits are saying that SCROTUS is already becoming a lame duck due to the economy and the Epstein scandal. Is that a signal of a MAGA meltdown? Maybe not a meltdown, but perhaps a 'shift' in which they are no longer afraid of raising his ire. I think they see that his 'power' is going to be finished after either the midterms or once he's out of office. And that if they want to retain their offices or be able to run again later they need to start cleaning the shit off their shoes.
There will be a special election to replace her some time after the 1st of the year. Unless the Dems conduct a planned 'migration' to the 14th, it'll be a Trump loyalist.