If you go with ariats, at least their lower-end range ones, make sure they're not too tall when they're right out of the box. I got the ariat heritage contour II as my first pair of tall boots. Normally they're supposed to drop so I got them slightly taller as people usually recommend, but they hardly dropped at all after riding in them once a week for MONTHS, so I'm stuck with tall boots that dig into the backs of my knees :/

Another more budget friendly brand is Mountain Horse, i've heard great things about them (specifically the Sovereign model, which also comes in multiple colours which is a plus for me!), I will probably try those ones next when I start riding again. But they are more expensive than the Ariats. I'm not sure how much they would cost in euros.

Also keep in mind that lower-end tall boots tend to have zipper problems based on reading reviews over the years, but I haven't had that experience yet.