If you want high frame over 100 consistently, 1080p is the way to go. 1440p is more like a 90fps at best experience for most titles even with a 2080 unless you want to play with lower settings. I prefer high frame rate and higher presets, it looks really nice. Also good 24" 1080p monitors are very affordable. Right now with less than $200 you can buy something like this
https://pcmonitors.info/reviews/aoc-24g2u-24g2/ it's very impressive.
For 1440p, you have to pay like 3 times as much which would have been fine if they didn't have so many issues. Market is filled with VA screens that are just not fast enough for 144Hz and the couple of IPS options have poor QC and just horrible glow. They are ok screens, just not worth $500-600. That's a lot of money for what you get. You can a buy a 55" TV with real HDR and 120Hz on black friday with that kind of money and connect it to your PC if you want a big screen. Monitors really don't go on sale much if ever. The monitor market is stupid.
1440p is just not very ideal overall imo. It's not high res enough to make you go wow like 4K is. The panels are mediocre. Video content scale poorly to it because it's not a standard resolution anyone makes content in. The monitor options aren't very good for the price.
I think switching between 1080p144Hz and 4K60 makes more sense you get the best of everything. You can actually get high frame and you can see high detail depending on the title you want. Fluctuating async 90ish performance is not as great feeling as 120-144Hz. You can even run titles like ACO at over 100fps at 1080p, at 1440p is just impossible.