Have you tried ComicBlitz?

Almost everything Valiant that's older than a year is available on Comixology Unlimited.

Unlimited isn't global. It's only available to the US (or NA) market. Outside of NA there is no such thing as Unlimited. The European version of comixology doesn't offer a monthly subscription service at all.

I can recommand InkyPen.

They may not have everything, but they have a lot of Valiant (even the old stuff) and they seam to be global

InkyPen is global, yes, but also strictly limited to Nintendo Switch.