Kurgarra have you tested sending or receiving MMS messages?
Well, I have seen some carriers able to get by with a single APN entry, I do not see anything regarding your MMS server or port, so I'm a bit curious to know if those would function.
You would be correct and that you will most likely have to either reach out to your carrier or, if this is an ESIM, you will need to reinstall the eSIM. You can do this in a number of ways, typically with an ESIM you do it through the app of your carrier. However, you can also reach out to support and they can either do it for you, or send you a QR code via email.
All you would have to really do is explain to them that you are only getting partial connectivity, just like you did here. "I'm able to do X and Y but I'm unable to do Z"
If you feel so inclined and technically savvy, it is also possible to do this manually. I've done it a few times myself. On both USMobile and Visible which are both Verizon MVNOs.
In both cases, I had to dig through their online documentation, which took quite a bit for one network, I cannot recall which, because they had outdated information. You want to make sure you find something within the last 6 to 8 months. I wouldn't go any further than a year. The trickiest part, however, while you were in the APN settings, did you happen to notice the three-dot Menu in the top right?
If you try to click this and it does not give you an option to Add, you may not have many options to do this yourself, while it is possible...it is lengthy and somewhat hairy to try and explain; I've only successfully managed to force adding and or editing while on a Samsung device. But I don't think I've ever encountered such an issue on a pixel device as they are quite open.
If you do manage to have an option to add, you would need to find the correct APN settings for your carrier and enter them very carefully as described in the documentation that you find. Make sure you follow the documentation to the T, rebooting whenever it tells you to and toggling airplane mode when advised, the reason for this is because it is essentially forcing a fresh reset of your network.
I've had to fiddle with my APN settings on both my pixel, due to a error that I caused myself, and on my Samsung, it was due to switching to a different carrier than it was branded with (T-Mobile to Verizon) and it was not properly downloading the correct APN settings. I would end up getting an issue. Pretty much exactly like yours where I would get X and Y but not Z. Once the APN settings are properly set and the device has been rebooted, you should have access to both data, calls, and MMS