aside from cucu, who else are we targetting? zinchenko's leaving so that leaves only cancelo (a right footer) in the LB position
2 out of 3, not bad (guess who's missing...).
We even have a good kid for LB in JWE.
Looking at the minutes, another LB would be surplus.
Cucu should have about 1,000 more minutes than Zin (had 1,840 mins),
Aké should easily play more (had 1,740 mins), while Cancelo should reduce at LB (had 2,800) and play more at RB (had 1,800).
Per position you can calculate about 5,400 minutes per season (that's 60 full matches which is near maximum).
Take a sheet and do your own split per position, it helps understand how Pep is managing game time.
Pep concentrates his subs on mostly mid and forwards for fresh legs in the creative parts, so 1 additional player at LB would cost a lot and would only make sense expecting injuries. Obviously we trust our medical department and try to optimize our squad (and sign players with a general versatility to cope longer injury phases).