I've done 3 or 4 Pixel RMAs and device protection plan replacements in the past few years. The good news is that it's relatively easy to convince them to replace the phone. I've never had a problem getting a replacement, even multiple times for the same issue. The bad news is that communicating with them is infuriating. In one case they were so incompetent that two different reps separately sent me replacement phones. And when I called them trying to return the extra phone they were totally unable to process the situation. I eventually gave up wasting my time trying to convince them that I should return the extra phone and just kept it (gave it to a friend). Luckily they were too incompetent to charge me for it.
The other bad news is that the Pixel 2 XL and Pixel 4 XL both had issues warranting RMA and the RMAs did not totally fix the issues because these were design defects, and the replacements also exhibited them to varying degrees. Speaker buzzing for Pixel 2 XL, and back glass detaching over time on Pixel 4 XL.
I'm still buying Pixel 6, but if it doesn't have an RMA-worthy design defect it'll be the first one since Pixel 1.