This is more of a “note to self”, but it may also be useful for others looking for a solution.

Phone: OnePlus 13, OxygenOS 15 (Android 15).
Bought in Israel.
OS version: CPH2653_15.0.0.840(EX01).

No “call recording” function in either the device Settings or the Phone app. The majority of call recording apps produce silent files even if they seem to run.

Good news! “Cube ACR” + “Cube ACR Helper” pair work well for call recording. Requires permission under Accessibility. Records call audio in both directions (incoming + outgoing) natively from the system, not via the speaker. Seems to use the audio channel intended for ASR (automatic speech recognition) uses, part of the accessibility features.