I believe you're describing the sovereign holding "allodial title", which is (mostly) true in all jurisdictions deriving from English common law, including, for

I believe you're describing the sovereign holding "allodial title", which is (mostly) true in all jurisdictions deriving from English common law, including, for example, the US States (well, 49 of them), so it's not a practice constrained to England and Wales, or to monarchy. (But IANAL.) I think some US States had a feature where you could pay a fixed amount to satisfy all future property taxes, but I don't believe it relieved the possibility of eminent domain, escheat, or police power.