Two things this will depend on - what are your system specs, and what games do you play.
If you’re on a mid/low end setup you’re not likely to be able to drive games at 4k, so go with the 1080p one. If you’re on a high end rig then 4k may make more sense.
Second thing is the games. If you mainly play esports titles that have low system requirements, you’ll be able to take advantage of more frames. If you play AAA/“cinematic” titles then 4k will be better.
Honestly though, my preference is 1440p at 120-144Hz. It’s a good sweet spot, just look for GSync support. Decent HDR is a bonus too.
If it’s in budget and you plan on upgrading then it’s not a bad idea! Personally I’d follow this priority for a monitor:
Figure out what’s important to you and try and find something that ticks as many of your boxes as possible 🙂