Operators don't like eSIM
Apple had to do a lot of arm twisting to get them to support eSIM at all - basically telling them "we're migrating off physical SIMs so if you don't support eSIM you will lose out on iPhone customers". So they've been forced to support eSIM, but that doesn't mean they have to make it a smooth experience.
I think it is hilarious that people actually believe eSIMs are some carrier plot to "lock in" customers. eSIMs make it (or would if not for the carriers hamstringing things) so much easier to switch carriers, or to have multiple carriers. My iPhone has two eSIMs but supports something like a dozen eSIM profiles. So I could have a bunch of different eSIMs available that I can instantly switch to in different countries to insure I always get the best rates, have a local number, whatever. It worked really well when I decided to test which of the three major carriers had better support from my house and from my mom's house. They offer free eSIMs good for a few days so I can switch to them and see how many bars I get, what sort of data speeds, and so forth.
eSIMs put the control in the customer's hands, or at least to the extent that the carrier either deliberately or through laziness adds friction to the process and doesn't allow it to be as smooth as it used to be. I switched to eSIM on an iPhone 12 Pro Max after using a physical SIM. I did it because I planned to upgrade to a 14 Pro Max and knew it would be eSIM only. It was a big pain in the butt to make this switch from physical to eSIM - I had to visit the AT&T store! Migrating the eSIM from the 12 to the 14 was a bit easier, but not much - I had to talk to customer service. I switched from AT&T to Verizon (Visible) the following year, I again had to talk to customer service (though most of my difficulties were with porting my number, another thing carriers deliberately add friction to because they don't want it to be easy) Last fall I upgraded to a 16 and the eSIM transfer was a bit easier. Not as easy as could be (Apple tries to do it automatically as part of copying everything to your new phone but the auto eSIM transfer failed) but I only needed to text a Visible CSR and they got it working right away.