How to enter download mode on T-Mobile's Samsung Galaxy S20 FE?

Whenever I try accessing download mode on Samsung Galaxy S20 FE, I click on reboot to bootloader but it takes me to a bootloader menu, where I get options like recovery mode, start, boot to FFBM, etc... yet, all of these options lead me into the main recovery mode menu. The phone is locked by T-Mobile and I think it may have something to do with it, I'm trying to flash the modem to unlock the phone. Any advice on how to get it unlocked?