I have 3 esims in total plus my normal sim. You can only use 1 esim and the physical sim at the same time. I would love to be able to use 2 esims but that's not supported.
While you can only have 1 eSIM active at any one given time, you can have several different phone number programmed into the the phone via eSIM. Not sure how many, but I did read someplace once that you can have up to 5.