The problem is only to get access to the site? I`m using the Brave, Chrome and FireFox browsers with different VPN addons and have no problem with it. And one more moment: these sites are banned only from your providers, or these sites don`t give a permission to use it for your country? Because if they banned your country - just look at other sites, you`ll can`t verify yourself without fake ID. And in such situation VPN is the smallest problem.
I think everyone know what is VPN, so that's why @OP created this thread for anyone who want to get access to blocked sites without installing or get subscription VPN. But he's not aware changing DNS is similar like you're using VPN and it will lead breaking their rules.
Anyway I want to ask to @OP how long you have using this method to play in blocked sites and how much you've deposited/wagered, the last thing do you ever faced a trouble e.g. your account got terminated or got asked KYC?