.Now people here and on other boards are saying some of the protectors at least do not play well with the finger print sensor. Will have to wait and see what the consensus is specific protectors once more people try them.
As it's an optical scanner, I'd be surprised to see much of an issue with a TGSP if people are setting up their fingerprints AFTER installing the SP, and turning on "increased touch sensitivity."
I have a cheap one I'll be trying on my 6 Pro on Monday, will provide link if it works well.
A couple of things I've read people doing that has given them better success have been to register the same fingerprint twice, and to turn off the animations in the settings. Coming from a Galaxy s20fe that only supports three fingerprint entries, and assuming that the pixel still allows for up to 10 to be stored (as was the case with the Pixel 3 XL) I'm hoping that that will do the trick.
In either case, I think it has to at least be good as the s20fe which uses an optical sensor, in which case I'll be okay with it as it was good about 90% of the time - not nearly as good as the capacitive sensor of Pixels past, though.
I get that they wanted to go for an aesthetic improvement by removing the rear fingerprint sensor, but really wish they had just integrated it as a capacitive sensor into the power button. That works flawlessly and easily 100% of the time on my Pixel Slate, offers the aesthetic improvement, and maintains what I believe to be the next best ease of access and ergonomic position.