For this purpose, even just having notes is sufficient. Eg:

2022-May-31 @ 11:09 AM: Spoke with X via phone, was informed their system was down and they could not accept my claim.

Recordings of the calls themselves can get murky legally, and are technically challenging, but in my experience factual notes are sufficient.

This. A detailed description of the call - what was discussed, who was discussed, what I said - reconciled with a record from the phone or phone company is more than enough. This is what many other professions, including medical, do.

If you're involved in a multi-million dollar lawsuit, sure you'll nitpick with lawyers about the content of the call, but for a few grand, no one's going to argue with you.

There's also too many headaches with recording calls. Dealing with one party vs. two party states, etc.

Hmm, then in sounds I can just record my own voice only. Notes are easy to write down later from those. Legally all is fine, since I'm recording only my own voice, but it's good for the purposes you describe.

I used to have a call recorder app installed on android, but some update removed that ability

Yep, I think there's no way to do that through API now, for security reasons.

There needs to be a dedicated "caller" app, and that app must be visibly different from default caller app.

Turn on speakerphone mode and use another device to record, your laptop should probably do the trick.

Do a written affidavit of the call post call?