2070S vs 2080S vs 2080TI for 1440p ultrawide?

I just ordered a 34" 1440p 120hz ultrawide g-sync monitor on black Friday. It will be replacing my cheap 27" 1080p 60hz monitor. So, a pretty significant upgrade. However, my current GPU is only a GTX 1660, so time to upgrade that as well. I understand that 1440p ultrawide requires a pretty beefy GPU compared to the usual 16:9 1440p. So I am considering going all out and ordering a 2080ti, specifically the ASUS ROG STRIX 2080TI. I feel that this card would atleast stay pretty relevant for 2 or 3 years. But at $1200... While I can afford it, if I can get the performance I desire for less, maybe the TI is just overkill.

I'd like a card that matches the monitor best. I play some pretty taxing games. Most currently Red Dead Redemption 2, in which my current GPU can only do about 50fps average on medium settings at 1080p. For this slower paced game I feel around 60+ FPS is fine, but I'd like to have high/ultra graphics at 1440p ultrawide. For FPS such as BF5 and the new Modern Warfare, I'd like ultra settings with atleast 90fps, which I think the 2080S or maybe even 2070S will do? I'm just not sure how the 2070S or 2080S will hold up over the next few years.

Anyone care to share their thoughts on this?.