Again though on my framwork-ification point -- in our case, we have a full VPC setup, and jets actually allocates the VPC for us we just configure it in our application.rb file. I'm sure the serverless framework has something similar. Either way, we have gotten away with not having a dedicated devops person or persons because of how much the framework does for you.
There's not getting around the networking and such - that's the full part of full-stack (FS) - it's more than simply FE+BE. Maybe call them distributed systems engineers instead.
What it sounds like though, is your organization (regardless of what we call it) is large enough to organize into FE, BE, and FS roles, with FS running the platform and being in charge of the fleet and for them to work on the system itself so that FE and BE can work without having to know about fleet - and FS folk are building internal tools that the rest of the org use to do their job, and to shield them from any of the implementation details your fleet has.