Yes, the board I'm currently using is gasket mount and sitting on a nice thick pad which helps, but what takes it to the next level is U4 Boba Silent linear switches, which are ridiculously quiet. Altogether I barely even hear myself typing, I can't imagine it's terribly audible over video calls.

I'm glad that this is the way customs are headed. I love my Think6.5 V2. Gasket mounting has been game changing for me.

After Googling for an embarassingly long time I think I'm figuring out what gasket mounting is.. how does that meaningfully changed how the keyboard feels? Just makes the whole typing surface a little flexible / bouncy?

I had to google this as well. It looks like the idea is to move the surface that the key switches attach to, to a sub-assembly, which can then be mounted in a variety of slightly-more-flexible sub-assembly. This is the kind of minutae I would have loved to get into when I was younger. The closest analogy I can think of is a solid body (standard) electric guitar, vs. a semi-hollowbody electric guitar, although the mechanics are very different, ultimately you're attempting to modify the percussive effect by modifying the frame.

https://keyboard.university/200-courses/keyboard-mounting-st...

https://www.sweetwater.com/c592--Semi_hollowbody_Guitars

There are a couple different techniques, but it really all boils down to dampening/softening the bottom out with rubber or silicone somewhere in the case sandwich. It gives it some “give” beyond the travel of the switch. A thick desk mat does this a bit too.

Are those that better than Realforce and HHKB?

They’re very different so it’s hard to say if they’re better. I find the stock HHKB domes way too light.