what kind of games are you going to be playing?
anyway the max you could get out of valorant is around 120Hz, but most of the other games you wont be able to go past 70-75Hz
another call for you to make is future upgradability, do you plan on buying a GPU if yes then go for a 120Hz
on the other hand if you have a real tight budget just go for the most proven monitor out there
i would go for the benQ 24inch FHD VA panel, I am personally using it and its awesome, most value for money monitor, deepest blacks, decent viewing angles... i've had it for like 6+ years now
now to answer your question "Will an upgrade to a 24 " with higher resolution and hz make a difference ?" yes if you move to a higher resolution you will see a performance change, keep in mind that the screen size doesn't matter but the resolution does
if you're super tight on budget let me know