Upvote:2
The curious thing here is that you state in your question that you have no problem with other sea level airports so it seems very unlikely that the usual tricks will work.
I would suggest either flying to Girona instead although there are fairly limited charter flights there and it is about 75km from Barcelona or even flying to Madrid and getting the AVE train which takes under three hours from central Madrid to Barcelona Sants station. You would still have to add in the time to get to central Madrid. If you are aiming for southern Catalonia Alicante might be another option for airports too.
Upvote:4
Since you stated you've tried (most of) the tricks listed on "Best way to make my ears pop", the only thing I can think of is taking an allergy drug that has decongestant in it (such as cetirizine+pseudoefedrine) about a half an hour before descend begins. Soma nasal sprays may also work. You should consult a doctor or a pharmacist for more detailed information.
And, as @abelenky stated in his/her comment, one should start "working" the ears as soon as the descend starts. If you have a tendency to get clogged ears, it may be that even a small pressure difference may totally block your eustachian tubes.