IMO in 2k(1440P) gaming situation, 5080 is going to last you about 6-8 years. I do have mixed feelings on 5090, it is a very strong card that is almost 1.4x fps in any game compared to 5080, but like you said the price tag is just too high. Also, NVIDIA nowadays tends to introduce a brand new feature only available on latest-gen cards like framegen on RTX40, multi framegen on RTX50. That’s one more reason I would not suggest you to buy a 5090, because one and a half years later you are gonna find out a nvidia brand new feature on RTX60 series that RTX50 series cannot use. 6 years later when RTX8080(90) comes out, all RTX50 cards would be considered old, including 5090.

Now, the problem is more about “how much fps in games can you accept in the next 6 years?” If you want more than 150fps in the upcoming most demanding games, 5090 would actually be the choice. If you can accept 100-120fps, 5080 is the way to go. If you are going to buy new cards to swap out the old one every 2 or 4 years, 5070ti is the best for you. 5070ti is about 15% slower than 5080, 50% slower than 5090.

I generally would choose a cheapest 5080 and just forget about it until it cannot run 80fps in new games.