Point me to the right hardware for a small project, please?

I have two 200Ah 12V Victron batteries collecting dust. I also have a couple different shop buildings that already have generator transfer switches on them (just small 30A 110V Twist and Lock plugs on the exterior). I was thinking a reasonable use for these guys would be to add an inverter/charger that I could use with the batteries to power one of the shops when the power is out if I wanted to. Ideally I’d have a power input plug, too, that I could use to keep them topped off when not in use as well as plug a portable generator in to as well if the power outage was too long for the battery.

What should I be looking at in terms of the hardware?