Two areas of concern: power outages and power surges.
For power outages you need a UPS with enough battery to provide time for a graceful system shutdown. Generally all that is needed is power enough for the computer and one main monitor. Speakers, second monitors, and so forth not really necessasry in most cases.
A UPS is not intended for continuing game play, working, etc.. Likely moot anyway if power is out.
Surge protection is measured in Joules. Each power hit will reduce the available protection. The reduction is cumulative: a few major hits, a lot of smaller hits, or some combination thereof. Sooner or later protection is no longer there.
Key is to determine the requirements. Most UPS manufacturer's provide some sort of guideling to size the UPS. Mainly how much wattage (VA) is required for x amount of time. Premise being that the end user is present to turn off the supported devices before the battery power is run down.
The guidelines often favor more expensive UPS units and the actual performance may be lab based (ideal circumstances) versus real world environmental factors.
UPS units can and do offer some amount of surge protection. How much varies with the unit and the actual amount of protection is likely overstated via one means or another.
Plus UPS's provide power to the served PSU using different methods: sine waves, simulated sine waves, square sine waves..... That can make a difference as to how well the everything actually works/performs when actually providing power. Some PSU's being affected by the wave form provided.
E.g.:
https://www.lifewire.com/pure-sine-...use it:,interference with modified sine waves.
I have two small UPS units. Just enough battery for a few minutes use to allow me time to do a normal shutdown. During bad weather, especially storms, I shutdown beforehand and unplug my systems. Doing that also reduces the possibility of damage due to power surges.
What to do:
1) Work out your power requirements if and when power is lost.
2) Read more about UPSs and surge protectors. From both manufacturers (biased) and reviewers (hopefully unbiased).
Hopefully you will be able to identify a UPS that will meet your requirements and budget.
There may be other ideas and suggestions in the meantime.