I've been a "couch" PC gamer since 2012, so here's my thoughts for your question.
Anything above a 3070 would be a bit overkill for you, I think. My buddy just upgraded to a 3070 after borrowing my 2080ti for a while last year (I built a new rig in 2020 with a RTX 3090 - MSRP). He said it's not a substantial upgrade from the 2080ti, but his set up is very similar to what you're after - 1440p at 144hz. A 3080 would give you a bit more head room if you plan on running Ray Tracing and the like. I wouldn't recommend lower than a 3070 right now, so long as you can afford it.
Additionally, I will say that DLSS is a game changer if you plan on checking out what Ray Tracing has to offer as it does give a significant boost to image quality and allows headroom for far more GFX options. Games with DLSS 2.1 are even better - evening out some of the artifacting that was inherent with the first implementation of DLSS.
Ray Tracing is generally better on Nvidia cards right now, and AMD doesn't really have a good competitor for DLSS in that space either. So, take that as you will.
Hope this helps!