So, I bought an account which cost quite a bit - everything went smooth, it was only linked to an Android. Now, in the back of my mind, knock on wood, i don't want the original owner recovering the account back. What is the best way to secure your clash of clans (gmail) account for future account recovering? (and I've done the basic ones adding in 2-Step Verification)
Best way to secure the account would be UN-LINKING the Clash of Clan account to its original gmail then LINK it to your own. This will involve contacting Supercell and request that you want the account to be unlink, they will ask you sensitive information about the account before they approve your request. Another option (Not 100% Guaranteed) is to make sure the GMAIL cannot be retrieved back, search how to retrieve a GMAIL in google so you'll have the idea of what you need to do/change from the GMAIL's information.