offlineimap and a few others do this. You don’t need to search for a Google specific tool but the tags might not map that well to folders, though if you treat them as folders it’s certainly imported. These tools are designed to take your (full or partial) mailbox on the go so you can work offline, hence they support incremental bidirectional syncing. Tools like offlineimap see quite some use so they should work as expected.

Not CoreXY but you may want to check out FLSun’s delta offerings too.

I have an older one and it has served me well. I bought a QQS pro (I think) for tinkering. It worked well out of the box but I could not resist changing the stepper drivers, installing Klipper, changing the hotend, … It still works well, just faster.

Looking at the few reviews of what they have today I’d buy again but would try not to swap out parts. That or the Prusa you’re looking at.