Question Using US version in Japan

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Anyone here using US version S22 Ultra or any US version Samsung phone in Japan?
Can you please tell me about battery life and are there any signal/reception/bands issue?

I've bought a t-mobile S8+ and at&t s7 edge on ebay before (around july 2017)
the s8+ was pretty new at that time, I think the battery is still very good but it would drain the battery from 100 to 10 overnight
just standing-by. I even made a factory reset and let it sit overnight but it still drains the battery so bad.
It was the same thing for the s7 edge I bought on ebay :(
I still don't know what's the reason why or maybe because of incompatible bands??? the phone is trying so hard to search for signal??
I have really good good coverage in my area though, I'm getting an average RSRP reading of -80dBm - -85dBm

I'm still hesitant about buying another one since I don't want to buy Japanese versions of Samsung phone anymore,
and amazon US the only option where I can buy new phone that ships to japan. 😅