As a newbie, you have not chosen a safer option instead, you have chosen complicated wallet options that could limit your potentials and have you confused in the long run instead, what can you do?

Get yourself a metamask wallet; store and secure your altcoins there and don't just connect your wallet in random places or websites you are unsure of. Then you can set up your trezor wallet and store your USDT there only.

As you increase your knowledge and learn more about using hardware wallets and some other perks; you can gradually move all your altcoins to the hardware wallet; as a newbie, always choose simplicity.