My forty years of experience rebuilding, repairing, racing, and representing race tracks and car companies has taught me that the tire manufacturer and model is MORE important that wheel size. I think
@MorganB proves my point: I am willing to bet the tires on his 20s are not Pirelli.
I really wish posters would put their tire make and not just the wheel size. 20s and 21s are NOT inherently horrible. Just more prone to issues due to shorter sidewall. You cannot abuse a 21 inch wheel. They are unforgiving. That is the trade off for handling and looks. Many people, here and otherwise, have NO issues with 20 or 21s. IMHO its NOT JUST THE wheel size - per se.
From what I see on the Lucid factory site, the 20s came with Michelin. The 21s came with Pirellis. So, those of us with 21s have two strikes: narrower sidewalls and the FIAT of tires (fix it again, Tony). I have numerous Audis for decades with 20s and never a ruptured sidewall - but I use Conti DWS tires.
If you are giving anecdotal reports on your tire/wheel experience, PLEASE tell us your tire manufacturer.