Going then in search of apps, a first solution is Call Recorder - Cube ACR. Download and use are free, but there is also a premium version. It costs € 1.99 per month and adds 4 features:
The management of the app has no particularities, but there is a limit to be taken into account. The software is only supported by Android 10. In any case it is not possible to record an ongoing call if it is on hold and if the audio is muted.
From one app to another, here is Call Recorder developed by lovekara. An essential condition for operation is the activation of the Accessibility function for the Call Recorder in the Services list.
Browsing through the list of apps on the Google Play Store one is at times amazed by the extreme variety of proposals. However, most of these apps are no longer supported by the new generation smartphones. Precisely because of the new Google policies in relation to call recording. The result is obvious: since the release of Android 9 Pie these apps are no longer usable.
Yet it is Google itself that provides one more option to record calls. There are 3 essential conditions:
At that point, you need to open the Phone app. Then at the top right tap on the 3 dots and then Settings and then Call recording. In the Register section always choose between Numbers not included in your contacts and Selected numbers. To record, tap Record on the ongoing call screen. To end it, tap on Abort instead.