I read through the thread and did not see any mention about possible mistake by OP, that Electrum wallet supported Legacy address in the past like 2016 but they disabled Legacy address creation with newest Electrum version.
Electrum generates a legacy address if you import a private key without adding any prefix. That hasn't changed and even in the latest version, that's still the same older versions.
For generating different types of addresses from a private key, you have add a prefix when importing your private key.