There are different LIPO chemistries. LFP in particular has little problem with being fully charged. You'll see it get swapped in for lead acid chemistries even in places like car/motorcycle batteries.
If you want an Lithium power supply then the keyword to look for is "LFP".
And LFP is also cheaper per unit energy and less of a fire hazard. Hard to imagine why you would use a different lithium-chemistry in a UPS.
Can't we just not push the lipos to 100% and have the UPS maintain a ~60% charge instead and get a long life span?
Many of these power stations (including the one I linked) are LFP chemistry