I kept my hair in small (not micro) braids with human hair for a 18 months, re-doing the them individually as my hair grew so as to avoid breakage/ lint deposits. I retained all of my growth for those 18 months. Taking me from about ear length, to APL. Neither my hairline or density were compromised. Best retention yet.
I did box braids and marley twists and crochet braids, all with with synthetic hair, throughout my two year transition but the growth wasn't as noticeable or as fast.
My hair retained length well with weaves (I've had two full sew-ins in my life). But I kept them in for like three or four months at a time and takedown was a thing of nightmares- it just was not for me.
Right now I am seeing how well I can retain my growth while enjoying regular wng and clipping it up (at least throughout winter). I don't bun, but I see this as 'my' wet bunning- although my ends are not hidden away.