> offering a product or service, the value of which entirely or primarily derives from the value of the Software or Modified version
How do you define how much value your app derives from Redis? If Redis is the primary data store for your app, does it count?
It will be if your app is a data store service . i.e. your apps is a thin wrapper around Redis.
If your app is more than that, then its clear the value does not primarily derive from Redis.
There are inevitably grey areas (e.g. if your app is a Redis based data store but adds a lot of functionality) but 99% of users do not need to worry.
Or I can just migrate my app to Valkey and be sure I’m safe from lawyers.
Nothing is definitely "safe from lawyers". In some ways BSD is less safe than SSPL - no patent licensing clauses for example.
> If you want to use a restrictive license, start your project with it, period
There is essentially only one restriction (the other is about formal notices) imposed by the RSAL, and it forbids to "Commercialize the software or provide it to others as a managed service".
> IMHO, small companies and developers ultimately lose here
This is an uninformed opinion. Nothing changes for small companies and developers. Actually, nothing changes even for larger companies, unless they are cloud providers.
Large companies can actually provide Redis as service for internal use ("as a service internally or to subsidiary companies"). Companies are even free to sell support for Redis.