I use CubeACR (find it in Play Store).
It bypass the limitations explained above by using the Accessibility options (If I understood well).
Works fine for me (NON rooted, stock Samsung Android 10 ROM, G973F dual SIM EU spec, 8-128 setup).
It records both sides and even Whatsapp and alike calls. The free version has ads (set up a private DNS if you bother that - I do, I would purchase the app but the creators only offer time-based subscriptions and not a lifetime license) and also the free version only record calls in .AMR format, though you can easily convert the ones you want to keep to any other format or simply let them as they are - recording quality is fine anyway.
Just follow carefully the setup wizard when you first start the app.
Give it a try, and you'll see. Hope this heps