California's landlord tenant statute also has a section that applies to Covid.
Law section (ca.gov)
From which I quote:
1942.9(b) Notwithstanding any other law, a landlord who temporarily reduces or makes unavailable a service or amenity as the result of compliance with federal, state, or local public health orders or guidelines shall not be considered to have violated the rental or lease agreement...
That tells me that if you get Covid and are required by federal, state or local orders to be quarantined for a period of time the LL is not going to be at fault for making you do your quarantine elsewhere.