I am native AmE. I agree that there are contexts in which "recommend FOR" might be appropriate, for example -- "My dog (you know who you are...) pulls very hard on the leash, so I'm looking for a collar that won't hurt his neck. What would you recommend for him?" But I suspect that "for" might not not be suitable here, as the Czech sentence uses a dative construction.
The sentence here is the formal (vy) version. The ty version uses "bys".
In general, ty and vy are not about politeness but about formality. The T-V distinction is given by the relation of the two people to each other. You must know whether you use T or V to that given person. It does not matter whether you want to be polite or not. Unless you want to be extremely impolite, then you use ty for everyone when heavily swearing.