Verizon demand that phones that work on their network include the privileged MyVerizonServices app. GrapheneOS does not include this or other similar privileged carrier apps.
The provision of the correct APN and carrier configs is surprisingly complex. There are some included in AOSP but they are often out of date or incomplete. We extract more up to date and complete versions of these files from each monthly stock PixelOS release and include them in our GrapheneOS builds. Some carriers have their setups provisioned via Play Store. We download these and also include them.
Verizon provisions the correct APN settings for Tracfone from the MyVerizonServices app.
There is an issue with the APN editor, which was recently rewritten in compose, which blocks the ability to edit the APN for tracfone. This issue exists on stock, but is a non-issue as MVS provides the correct APN.
We do not have developer resources available to work around these issues.
Suggest you change to a different carrier.
Theres been issues with tracfone for some time
https://github.com/GrapheneOS/os-issue-tracker/issues/2299