(with a couple "backups" for good measure)
In the case of GA, with a (R) Governor & (R) legislature, when they saw that Ossoff had actually come close enough to Purdue to have to do a run-off, and Warnock's first special election run that Nov. 2020, also required him to do a run-off, those 2 circumstances seemed to be the canary in the coal mine there (and that's not counting the Stacy Abrams factor although she couldn't break through the Kemp wall).
Similarly, AZ had a (R) Governor and (R) legislature (although a (D) SOS) and then you suddenly had a " (D) " (in quotes) - Kyrsten Sinema, flip Jeff Flake's (R) seat in 2018 and another (D) - Mark Kelly - eventually flip McCain's seat the following year in 2020. More alarm bells to start attacking the elections.
So with the above 2, they were hoping their GOP buddies would "go along".
Here in PA, we had a (D) Governor and SOS but a (R)-controlled state legislature, so they wanted to try to do their shenanigans with Ghouliani's help by throwing lawsuit after lawsuit against us here, while attempting to rally the legislature to do anything in their power to reverse what was looking like a flip back to blue - possibly thanks to the-then brand new "no excuse absentee ballots" that the (R) legislature almost unanimously enacted (save for 1 GOP legislator). Before 2020, the last time PA voted (R) for President was 1988. What helped here thwarting some of the lawsuits was that PA had a (D)-majority state Supreme Court.
WI and MI both had trifectas at the time but they also had some (D) Senators (Debbie Stabenow and Gary Peters in MI & Tammy Baldwin in WI), so that was more "warning signs" for them that those states could flip back.
NV and NM were odd borderline ones for them but NM had a (R) Governor at least through 2018 as did NV.
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