Interesting. That sounds like a rabbit hole, as I originally created the wallet from a BIP39 seed. Perhaps there is something different about BIP39 I don't understand. And, maybe, Electrum takes a different approach than other wallets like Exodus.
If you have generated your seed phrase using electrum itself, it's not BIP39. Electrum uses the same wordlist as BIP39 for its seed phrase, but a different algorithm.
If you have generated your seed phrase somewhere else like exodus and imported it into electrum, your seed phrase is likely BIP39.
I suppose this is why my legacy Bitcoin UTXOs don't show up if I choose a Segwit wallet and visa versa.
If your seed phrase is BIP39, you are asked the derivation path and script type when importing your seed phrase.
If you have fund in the legacy wallet and you choose segwit when importing your seed phrase, you will see completely different addresses.
I'm trying to access some alts with the same seed.
For more security, I recommend you to use a separate wallet for your bitcoin and avoid importing your seed phrase into different softwares as much as possible.
The more softwares you import your seed phrase to, the more attack vectors you may open for hackers.