Have low-end UPS units gone lithium iron phosphate yet? That's the battery technology of choice now for non-portable applications. Cheaper and longer-lived than lithium-ion, no thermal runaway risk, about the same energy density per cubic meter, but twice the weight.
Such UPSs are available in small rackmount units.[1]
The usual serious players, such as Tripp-Lite, have LiFeP04 battery powered units.
Searching for consumer-grade LiFePo4 UPSs turns up many articles on how to replace crappy batteries in UPS units with newer battery technology. The batteries themselves are cheap now.
APC doesn't seem to have caught up yet.
Such UPSs are available in small rackmount units.[1] The usual serious players, such as Tripp-Lite, have LiFeP04 battery powered units. Searching for consumer-grade LiFePo4 UPSs turns up many articles on how to replace crappy batteries in UPS units with newer battery technology. The batteries themselves are cheap now. APC doesn't seem to have caught up yet.
This looks like an APC corporate problem.
[1] https://www.falconups.com/ups/lifepo4-ups-sl.htm