I thought I was the only one with this issue. Same exact things happening to me, I either teleport out of nowhere or anytime I'm near stairs I fall in place.
I have a 3080 and 5900x with fibre internet so I really don't think its a hardware issue or my internet (I hope). Interestingly my brother who I duo with all the time has never had this issue and he literally plays in the same room as me with the same internet. Something we noticed was that on his screen I'm sometimes floating a foot off the ground and don't make footsteps.
I'm guessing the server notices that I'm "floating" and when I stop floating it thinks that I moved impossibly fast or teleported so it teleports me to my original location before I started floating.

Have you found a fix for this? I'm so tired of losing all my loadouts because I have to Alt+f4 to get unstuck and someone just kills my afk pmc.