U prob wont get this answer from others:
A UL458 inverter doesnt require ground. Complicated yada yada about its internal makeup.
Because UL458 is 1 of only 2 UL listed off-grid inverters. Theres the 458 which is mobile off-grid like a boat or RV. Then theres the UL1741 stationary off-grid like foe a cabin, shed or home.
Ur lucky cuz the UL458's r a lot more available. Like I buy AIMS mostly but of their UL listed inverters, only 1 is 1741 with rest being 458.
Of course caring about UL listing is up to u. For myself, Ive become the solar UL YODA. Thats cuz everything solar in my county must be UL listed.
Btw u wont need much for ur project. A 2500 or 3k inverter would give u some padding and still be cheap. I would go 24v battery bank... thats my preference.