You can import the Trezor seed phrase into electrum because the wallet is compatible with Bip 39 seed phrase which Trezor uses.

But why do you want to import your cold wallet to an online wallet, all what you need I just to create a watch only wallet by importing your master public key to the electrum wallet.

Also if your concern is about importing your Trezor generated seed phrase to any wallet in future then there is nothing to worry about because the seed phrase is in BIP 39 format or compatibility and there will be wallets to recover it no matter the length of the word. Wallet like BlueWallet can do that, electrum also can