I did further experimenting to see what works and what doesn’t so if anyone else comes across this before the next software update, maybe the info could be helpful.
I tried to activate an eSIM with Google Fi after transferring a number over I had on a spare Verizon line. Fi typically requires installing the Google Fi app and the app of course requires Google Play Services. Fi has an iOS or tablet activation QR code available, so I used it to successfully download an eSIM and then manually inputted the APN settings provided by Fi support. I was unable to get any service because the number porting process wouldn’t finish without the Fi app.
I activated the eSIM on a spare Android phone to complete the transfer, and then was able to use the Kompakt as a data-only device. I am awaiting physical sims from both Fi and T-Mobile in the meantime to see if it can function as a primary device with calling and texting enabled.