I have flashed but I've been using pixel. 3a is prob the lowest you can use for de-googling and it's still a good phone but much older now and small.
5a is very decent still.
You can go higher ofc.
Discussion
I was going to look into the pixel 7 series to see if its worth it. I know some of the Pixel generations were barely an upgrade from the last so if 7 isnt much better than 6 I'll probably go lower.
6 is when there's no more earphone jacks.
I like that option so...I'm staying under 6.
And 6a wasn't that much an upgrade from 5a either