I don't know any site that is compatible with Electrum's seed phrase when you import a wallet
Electrum is an open source project which can ensure its continuity, it is the most recommended light client wallet on this forum, Electrum incompatible seed phrase on BIP39 wallet is as a result of version number included to generate keys and addresses which also check seed integrity as Electrum seed phrase must produce a valid version number. It is the best in my opinion.
I have imported seed phrase generated on Electrum wallet on Bluewallet countless number of times and it was successful, but just for experiment purpose, I have not seen a need or a valid reason I should import Electrum seed phrase on any other wallet. Although, Bluewallet is also a good open source wallet.
If you still want BIP39 seed phrase to be used by Electrum, Electrum wallet still support the importation of seed phrase generated from BIP39 wallets. You can generate a BIP39 seed, import it on Electrum, check the BIP39 option on Electrum and choose the derivation path of your choice as seen below.
Legacy (p2pkh) for bitcoin addresses that starts from 1
p2sh-segwit (p2wpkh-p2sh) for bitcoin addresses that starts from from 3
Native segwit (p2wpkh) for bitcoin addresses that starts from bc1
But I will recommend you to use a reputed and open source BIP39 wallet like Bluewallet, Mycelium or
html file of Incoleman BIP39 tool for the seed phrase generation unlike using a close source wallet like Trsutwallet which are not advisable at all.