Not sure, but if the gambling website doesn't required kyc and the account is not kyc verified yet, I guess that's okay. But if the account is already verified and is on sale, then I guess it's sus since there are several incidents of identity thief, though I'm not saying OP is but it should be suspicious selling account's and personal info.
Yep, +1 merit from me for this take.
Also, another common situation is when people selling some accounts with a variety of problems on it. Like disabled withdrawals, bad reputation or something like that. Or, more cunning, when people selling (it's often happens with books in my country) acc with decreased withdrawal limit, but not like 0. You doing test with amounts like 100 dollars - everything is fine. You buy it, deposit 1000 dollars and for some reason try to withdraw 500 dollars back. And you can't because 500 dollars if above limit
So it's not very good idea to buy someone's account