If we are to even consider the replies on this thread on recommendations for the platforms that accept the use of VPN, I don't think there are suggestions made and if any at all, they are not many, gambling platforms don't usually demand or take in the use of VPN for their website, but Incase we see some that allows for that, maybe they are just new in the business or doesn't have enough resources to employ for the measures that take care on that.
I used this site stake.com through vpn but didn't face any problem. But I personally don't recommend anyone to run any site using vpn. Because using vpn is very risky, any company can restrict the account if they want, because I have not seen permission about using vpn in their TOS. so I would say that sites which can be accessed without vpn should be used for gambling and should not be used for high amounts because gambling should only be for fun.