Don't put a deep-cycle SLA or gel-cell battery in your UPS. It will last a much shorter amount of time (2-3 years vs 5+). I do not remember the specifics but it has to do with how big the plates are and how thick the internal connections are in the battery. Designing this chemistry of battery is about trade-offs and unless you greatly oversize the cells and do your own install externally it will wreck your battery longevity.
If you want to maintain spec in something like an APC UPS, buy CSB batteries (which is what APC slaps their sticker on) and get something from their GPL line https://www.csb-battery.com.tw/english/01_product/00_overvie...
The real disruption for UPS's are the switch from SLA to LFP cells, but power density isn't as good so they need to be sized up a decent amount to handle standard loads. But the chemistry is a ton better.