$200 and UPS, doesn't buy much.
My interpretation of an "Online" UPS is a double conversion UPS. That is a UPS that is always creating AC from DC. It has a constant voltage output.
To get a UPS, you first need to measure the actual wattage used by your PC during the most strenuous usage. For most people on this board, that would be gaming, but your usage might be video transcoding. Whatever puts the most load on your PC is where you need to measure the ACTUAL wattage.
I recommend something like this (US model shown) --
https://www.amazon.com/P3-P4400-Electricity-Usage-Monitor/dp/B00009MDBU But there are similar devices for other countries.
Once you have an ACTUAL wattage, you can size the UPS. If you really aren't worried about power outage run time, you can get the smallest double conversion unit you can find. That is generally a 1000VA unit. I recommend buying a used commercial double conversion unit like an APC Smart-UPS ONLINE. Something like this --
https://www.ebay.com/itm/364671217138 . Ask them to ship WITHOUT BATTERIES to minimize shipping cost. Then purchase a new battery pack.
I have 3 units just like this one at my house.