Generally, the SuperDraft does not play a significant role in MLS anymore, especially in comparison with, say, 10-15 years ago. Back then, it was common for 1st and some 2nd rounders to come in and win starting jobs and get significant minutes. It’s been diminishing in significance gradually, but consistently, since then.
Most of the players drafted now do not play initially in the league, or at least get much playing time. There have been a handful of drafted players that in recent years have had big impacts, even some going on to play in Europe. But it’s largely a crapshoot about who will succeed.
Coverage of college soccer is minimal, so it’s hard to get much insight into players who might be drafted until very close to the draft. The MLS site usually has some coverage around that time, but it’s not super in-depth. TopDrawerSoccer has probably the best coverage of college soccer, but most of it is paywalled:
https://www.topdrawersoccer.com/
This is a good article surveying current dynamics:
https://www.mlssoccer.com/superdraft...to-today-s-mls
Also, MLS roster rules, in all their complexity, can be found here:
https://www.mlssoccer.com/about/rost...nd-regulations