Sevilla won three Euro cups in a row, Real 3 CL, Athleti have won 3 EL since around 2009 Barca have won 3 in recent times. They have had a strangle hold on the competitions in recent times. You just have to look at Coaching license numbers per country Spain out numbers England 9-1 just on these figures alone. Coaching, youth development and technical ability is streets ahead in Spain it’s not even worth arguing.
The EPL has a high standard due to the influx of cash and foreigners and it’s a league focused more on athleticism.
La Liga is a far higher standard technically it’s not even up for debate there’s a reason why the best players in England ain’t English
None of that is in any way related to your point though. It doesn't matter whether the best players here are English or not, they're still here, and so they still count towards the technical quality of the league. You've also used the example of the same 4 teams that the poster you were replying to had said they were discounting as the point was about depth.
To me it depends what you class as technical quality. Is a defender who has a great touch and passing ability but can't head, tackle or intercept technically good or technically bad? Are we judging them on the technical skills most relevant to their role, or those most pleasing on the eye?
Anyway, looking forward to see Mina when he eventually manages to get himself on to the pitch.