Yes. Regen is only capable of what the battery can take in, which is limited at high SoC or cold temps. E.g. see https://electrek.co/2022/05/25/tesla-updates-car-software-re...

You still need friction brakes for everything else, which in Teslas (and most other cars) are hydraulically actuated.

Regen braking works by letting off the accelerator, not by pressing the brake.

Yes and no. A lot of EVs can do two different modes, where it "coasts" and mostly only starts the regen through the brake pedal. You're right though, from what I understand Tesla kind of forces the single-pedal driving mode.

You can't disable one-pedal driving? No wonder I see so many people in Teslas randomly flashing their brake lights on the freeway.

You can

Eh, from what I understand Tesla has made a number of changes to the configurability to regen. I don't drive a Tesla so I'm not entirely sure what that means in terms of single pedal and the overall driving feel.

https://teslamotorsclub.com/tmc/threads/21-myp-how-to-turn-o...

The parent comment specifically asked about a Tesla.