No, your UPS is tailored to the characteristics of the lead-acid charge/discharge cycle. Some LiFePO4 battery assemblies are built with charging electronics that simulate lead-acid for a drop-in replacement, but those are never cheaper than traditional lead-acid batteries.
They are kind of like two hands making a handshake - they just twist/slide into each other and each is then looped around the back of the other. Very simple and effective
Have you seen these knife connectors used in aviation? They are genderless and lock together. Of course your crimp better be solid - meaning proper connector for the wire size and proper crimping tool die.
our oven has a “kitchen timer” and a “cook timer”, the first does what you say, the second turns the oven off. Maybe there’s another option?