I feel like it might be really awesome to have that complete firewall between work and life comms.

Reportedly, many firms had an SSL MITM server in place and also recorded your private Facebook messages if you made them from the office wifi. Signal conversations may have been safe, but that's it.

The work Android or iPhone records calls? Is it even possible

It's all just data, isn't it?

Route it all through VoIP and record it there?

Maybe theres some bank-compliance phone vendor that operates its own MVNO and does the recording for you?

here's something like that - https://www.teleware.com/products/mobile-voice-recording/

No it’s not possible in the way or manner you described unless it’s an office phone.

Banks aren’t creating a super secret MVNO to comply with regulations and the telcos aren’t cutting breaks for a bank or a 3rd party spy network. I’d imagine saving all employees cellphone calls for 7 years is a very expensive project.

You can encode voice with quite acceptable quality at 8kbps. (With recent advancements even 3kpbs is reasonably good.[1]) That’s 3.6MB per hour. Assuming an average of one hour per workday on the phone, a single employee generates less than 1GB a year. That’s peanuts. Even eight times that is lower than what I personally generate every day.

[1] https://ai.googleblog.com/2021/02/lyra-new-very-low-bitrate-...