When a samsung smartphone is rooted with MagiskHide, how to restore widevine L1?

Using MagiskHide against all Google services and clearing data, I restored the widevine L1 level in the DRM info app. But now, all the video services that are widevine L1 only idle when attempting to play a video instead of properly showing an error message (so it’s don’t work). As far I understand, videos decryptions keys are erased from the trusted keystore of the cpu in case the firmware is tampered. If this is true, how to restore them ? If not, how to access apps that require widevine L1 access (not accepting widevine L3) ? I’m asking this because several post across the Internet emerged in claiming on how to restore widevine L1 and by following them the device is again signaling the compatibility with L1 but doesn’t seem to support it again in reality.