Did scholars define a limitation of concubines a man could have?

While verse (4:3 ): > And if you fear that you will not deal justly with the orphan girls, then marry those that please you of [other] women, two or three or four. But if you fear that you will not be just, then [marry only] one or those your right hand possesses. That is more suitable that you may not incline [to injustice]. gives a limitation on the amount of wives a man can be simultaneously married to. Just out of curiosity I'd like to know whether this applies/applied● also to concubines (slave girls) or if there is any ruling or a consensus about a ruling giving a limitation of concubines a man could have? ● IMO slavery is no more legal even as all Muslim states have officially declared it as such