What info do i need to backup in order for the seed phrase from electrum can be used by any other wallet?
You can export the master private key. It can be used for deriving all your private keys.
To do so, go to console tab and paste the following command.
i thought i could recover any bitcoin with a seed phrase but its not true from what i understand
Electrum seed phrase is enough for recovering your wallet.
Note that all your keys (private keys, public keys, addresses) can be derived from electrum's seed phrase.
If you think that electrum may not exist in future, there is no need to worry about.
Electrum is open-source. In the case developers leave the project and the website shuts down for any reason, there will be other websites hosting the code.
Also, you can use
blue wallet for importing the seed generated by electrum.
(Just note that electrum's wallet can be imported into blue wallet only if the wallet has been funded.)
If you want to have a seed phrase that can imported into almost all other wallets, you should generate a BIP39 seed phrase. Electrum doesn't do that.