This is just my opinion but I wouldn’t waste time or money on a manager in the library end of things.
I also come from the band/performance end and we had a manager and someone pitching our stuff but when I started doing production music I never even thought about it.
I guess if you start scoring major films or want to then an agent would be needed but for now I don’t think you need one.
I think this may have been covered in an older post at one point and the general consensus was leaning toward no manager.
Just speaking from my experience ymmv.
BTW, congrats on the Crucial acceptance, they are a tough nut to crack!!