In view of the title, before starting to whistle and spit, let me make two points: one, in principle, I am against the real system, wherever and whenever I want, two, what I would like with Spain, is a cordial diplomatic relationship.

However, I have never been satisfied with the sympathy of many of us towards the Spanish Republic. No to history (chap. The republic was petty and blind to us, and the only reason for sympathy would be the horror that followed later), not the third century. To a possible republic.
In its five hundred years of history, Spain has always focused on the plundering and oppression of peoples; this is not so rare, the states around it have done the same; it would be a singularity that, apparently, this attitude is incorporated into DNA and that sees the denial of peoples not as imperialism but as a right; always with our purposes.

Ethnocentrism, desidia, caciquism, Catholicism and monarchy are five hallmarks of the identity of our local people, almost always tied. Would we be kinder if we lost any of them? Some believe that without monarchy the multicultural and plurinational character of the State would be better recognized. I doubt it: see France, so secular and republican, more eternally than anyone else.
If Spain chose a president of the Republic, it would always be a state party, and its action would necessarily be centralist. In theory, a king or queen may be more respectful of the peoples and languages that make up the kingdom (I know what the practice is here, but the Belgian crown is inevitable in this field).

I am convinced that for Euskal Herria to live we need independence, but two findings: they will never give us much and there are no conditions to achieve it by force (it was clear for some time, but now everyone recognizes it, and better); from political fiction, we could imagine a quasi-independence state; and those, not in the imagination but in reality, have been carried out with the British monarchy: the Comwealthian.

We all hate the bourbons, all right, but who wouldn't sign the status of New Zealand or Canada? And now yes: you can start throwing stones and whistling if you want.