"safely" is debatable... Note that these exchanges are NOT run by Trezor. They are 3rd-party services...
The digital asset exchanges available on the Trezor platform include Changenow, Coinmama, Changelly, Paybis, and Coinswitch
Several of these exchanges have been reported as engaging in somewhat dubious KYC procedures... as in, waiting for user to deposit large amount of crypto and then demanding KYC completion before releasing or returning funds.
This.
I'd recommend everyone to rather use an proper exchange (if possible) instead of using such services.
Not only those KYC-scams, but also the lack of verifiability and transparency are a big red flag for me (not mentioning all the attack vectors here..).
Currently there are scam accusations open against changenow. So, i'd probably avoid them if possible.
If one really has to use such a service and there is no other possibility of using an real exchange, i'd probably rather use changelly/shapeshift than anything else (simply because they are the 'most reputable' ones).
But IMO it is way safer to send your funds to an exchange, trade and withdraw, instead of using such a service.