My vote would go to Alcudiamar Marina in Port d' Alcudia in the north of Mallorca, in the Balearic Islands, part of Spain
. My boat was based there on annual contracts for 10 years while I came and went from UK (not part of Schengen). Apart from the usual passport checks at Palma airport, i was never asked for anything by anyone.
The area is a bit touristy without being overdone and is very scenic, next to the World Heritage area of the Tramuntana mountains. You have lots of good local sailing possibilities around Mallorca, Minorca and further afield if you want. The port has every marine
facility and a good range of local marine
trades if needed. The marina itself is extremely well sheltered and has good security
If you stay away from the obvious tourist hotspots, Mallorca itself is extremely beautiful, and in the local area around the Marina you have the old towns of Alcudia and Pollensa, as well as the resorts of Port D'Alcudia and Port de Pollensa. The city of Palma is a popular cruise ship destination
and is about a 1 hour bus ride away, also has its major airport with connections all over Europe
Gets very busy and hot for about 8 weeks during earlyJuly to early September but is otherwise surprisingly civilised. Also enough of a real local community so still has plenty open all year round.
Worth a good look for part of your time and very convenient.