I've learned that it's impossible to record calls with GrapheneOS, so I'm thinking about the following mobile setup, with 2 phones:
1 - Some random stock phone with a SIM that I'll use for calls, SMS and a hotspot for the 2nd phone.
2 - The GrapheneOS phone that is connected to the internet through the 1st phone's hotspot. Traffic will be routed back home using WireGuard so it's hidden from the stock phone and I'm able to access my home server.
This way I'll be able to record phone calls, and decrease the attack surface on the Pixel by not connecting to data. If the 1st phone is breached, communication through it is encrypted anyway (WireGuard on the GOS phone) so it's not a big deal.
And yes I'm willing to carry 2 phones if that setup makes sense. Does it though? Security & convenience-wise (besides having to carry and charge 2 phones)