Believe it or not, California no longer allows blanket at-will evictions as part of it's recent rent control law. Landlords still have more leverage than tenants but it's a bit better.
Sure, it's not "at-will" and you can fight it, but it sure does feel lopsided if you can be told at any moment to find another place to live in one week for any one of a host of reasons you "agreed" to that change constantly.
Contracts just generally can't preempt rights. Of course, the type of contract is important. Ordinary residential tenants have rights. If you're a commercial tenant, any imaginable conditions are possible.
[1] https://selfhelp.courts.ca.gov/eviction-tenant/notice-types
They were clearly boilerplate forms, from several sources (hence the overlap and contradictions), "If any terms of this Addendum conflict with the Lease, the terms of this Addendum shall be controlling," etc., 6 documents and 20 pages after some other terms on the same subject. I claim to have read it, but I make no claims about having understood it.
There is an asymmetry of resources here that gives a large property management company a lot of ability to make your life unpleasant (and rent control gives them a good reason to want to). By the time you end up in court you have already lost.