Tootfinder

and so, once again, the 'solution' isn't in the distro or legacy, it is in the wiki on the internals of Evolution where I just incidentally learn it can be a flatpak or not, and thus there are TWO .local/share folders to wipe. So I delete all accts in Evo, empty trash just in case, exit, wipe those folders, go into Settings, delete the Google connection which shows as two identical so delete them both, reboot.
On boot, go straight to settings which shows none, add Google and I'm in, quick as a wink. I start #Evolution, and lo, there it is, my account fetching emails!
Now to figure that #mastodonel thing and why mastodon.plstore is so problematic.