i seldom get my PC in high load; should I get those high price range UPS?
depends on your usage and appliances total power consumption, I am sure you wouldn't just plug in your PC only right? I use it for my routers, ONT, NUCs, NAS, ext HDD (connected to 2 UPSes) as well so you'll have to take into account of those sensitive equipments you intend to protect.
When UPS is overloaded, it will not cut off power directly but will gives out a irritating warning siren.
Better to allocate more VA for future peripheral expansions than to scrimp and find out you run out of choices.
If budget is a constraint the APC Easy series is cheaper (budget end) but it doesn't seems to be able to replace batteries (please research)
Based on Amazon.sg, this is your baseline
https://www.amazon.sg/dp/B07WJ4ZRWM/ref=twister_B08XZQN727?_encoding=UTF8&psc=1, I am not sure how much power your 3080ti going to suck at full perf hence better to allocate more than less.