I have flashed Iode 7 on a Pixel 7 this week but have found that mobile data doesn’t show as working unless Wifi is turned on.
I have tested this with two physical SIMs (Smarty - a 3 brand) and Spusu - an EE brand) and one eSIM (Spusu). The physical SIMs didn’t connect at all, just showing no signal and a bang character. The eSIM shows a connection but there is no data connection. Phone calls work correctly.
The eSIM was installed using the system installer, but it shows in OpenEUICC as expected.
The phone was bought second hand from eBay but I didn’t check what stock firmware it was running.