He is massively underrated by Barca fans generally.
His skillset is as wide as any midfielder player in the world. How many midfielders can you name that can do the following all to a high level.
Dribbling
Long range shooting
Finishing
First touch
Long range passing
Short passing in tight areas
Crossing
Tackling
Pace
Decision making
Awareness of teammates.
With him being so young, he will improve a touch on all of the above as well as improving on his biggest achilles heel at present .... His consistency.
Selling him would be a huge mistake and I honestly see him becoming one of the best midfielders in the world in the next 3 - 4 years.
It is myopic to think one pass/assist in a whole match where you turned over many others, misplaced about 9 or more other ones that could have led to goals, suddenly makes you a top talent. It is beyond ridiculous to boldly extend the evaluation to a global level when the sample size of the matches he plays is limited to cameos and substitutions due to his limited talent. I dont have a problem if people have a low bar for evaluating excellence or talent in their teams, myopically extending it to the whole world is another level of ish for me.
Truth be told, if Barca never ran into the murky waters of financial mismanagement, a player like Fermin would only be viewing Barca matches on TV screens.There were players with far better potentials at Barca B that were shown the way out much earlier. Fermin is poor technically, he is average in all of those things you listed. His statistics on pass completion rate, successful dribbles and rate of turn overs(Google works too) should tell you more.