StringToRedisValue

Oh dear, it looks like you fell into a DEBUG warning. Don't panic! You're probably fine.

Short version, if you're in the core library when seeing this:

If you're writing data (to the server), you're probably fine - just add .AsRedisValue() to say "trust me bro"; all strings are valid as RedisValue content - you're fine. If the value is a literal (i.e. "some const string") or a const, you might want to look at RedisLiterals and the .FromRaw(...) API, which can be more efficient, but otherwise: you do you!
However, if you're reading data (from the server), then you need to be careful - there's a good chance you've used reader.ReadString() when you meant to use reader.ReadRedisValue().

The impact of 2 would be that string payloads work fine, but you silently corrupt binary payloads. Additionally, if the value is small or an obvious integer, RedisValue may be more efficient (zero-allocation), and even for non-trivial text-like payloads: using RedisValue defers the UTF8 decode cost to the caller. So: ask yourself - is this actually a string in all cases?

This warning only exists in local DEBUG builds - it doesn't exist in the public package.

If you're actually in an auxiliary package (tests, benchmarks, etc): we care less. Feel free to add <NoWarn>$(NoWarn);StringToRedisValue</NoWarn> to the csproj.