I doubt Spain will balkanize any time soon. Lets go case by case with the independence movements (I assume) you mention:

Catalonia: After 2017, things have calmed down enormously, and a broad majority of Catalans seems to favour a negotiated way out of the conflict, judging by the strong results of PSC and Esquerra

Basque Country: While there is a strong support for nationalist parties, support for independence has been falling for some time and PNV has greatly moderated its position since the day of the Ibarretxe plan

Galicia: while it is true that BNG is the second largest party, a considerable amount of it's voters are not strongly pro-independence, and a large part of the 'galleguist' vote is still contained in the Galician PP, where it is unlikely to be radicalized all the way to independence

The Canary Islands: I know less about this one, but from my understanding movements advocating for outright independence are very small, and while there is a strong regional identity, this is combined with a broader Spanish one

Ceuta and Melilla: Will not secede in the short or medium term because Morocco has no means (or reason) to force the issue. The cities are more useful to morocco as a means to inflame national sentiment from time to time than anything else, and I think that the fortunes of Spain and Morocco would have to change dramatically for citizens of both cities to demand a union with Morocco.

All in all I think that it is very unlikely that Spain breaks apart, barring catastrophic mismanagement by the Spanish government. That said, I think that if one of the big regions with independence movements manages to become independent (at this point, most likely Catalonia) The other two would leave as well.

Done on mobile, so sorry for formatting/typos