I just want to separate like your suggestion, Trezor for a cold wallet, and Electrum for a hot wallet.
You already have a "
convenient cold-storage" which is your Trezor, just use it instead of creating a hot wallet with less security.
The only hard part of using it is when plugging and signing transactions which IMO, isn't that inconvenient.
but, because it's enough completely, maybe better to create another address on Electrum just for use for frequent transactions.
There is an easier solution, which is to extract Xpub aka Extended Public Key,
The alternative to that solution is to disable wallet encryption.
That way, the wallet can be opened without the plugging the hardware wallet, it'll only be required when the keys are needed.
There's no private keys in the wallet file so there's no major issue aside from privacy issue for when the unencrypted wallet file got in the hands of a hacker.
(
the public servers if you're using those already know your addresses anyways)