VISIBLE NOW SUPPORTS ESIM DOWNLOAD!
I was checking my Visible app today and it offered to move my SIM to the phones ESIM. It worked after I figured out what it wanted. If it asks for your IMEI, you need to give it the IMEI from the slot for you ESIM. On my Pixel phone, I have one physical only slot and one ESIM only slot. Initially, I thought they wanted the current IMEI from my physical slot but the program barfed trying to download the new ESIM to the physical slot. After a chat with Visible on the app, they told me to remove the old SIM card, remove the Visible app, reboot the phone and reinstall the Visible app. When I did all that and accessed the Visible app again, it downloaded the ESIM correctly.
This way, if I want to check out other carriers, I can use the SIM card they send and not worry about not having Visible working at the same time.