I love Pieces & Peace, they produce in France and have some really pretty puzzles. Though they might not be dreamy enough/too colorful for your taste, but give them a look: https://www.pieces-and-peace.com/our-story.html

Castorland is a Polish company, I have a couple of their classic art puzzles. They are on the cheaper side, but Quality is not bad. They tend to have smaller pieces than other companies, which means their larger puzzles by number of pieces don't take up as much space. Their art work is often pretty cheesy, similar to Ravensburger, but they also print beautiful classic art, and their styles are very varied, so there might be some you like. https://castorland.pl/

Vissevase is a Danish company and mostly designed by one artist, I think. They are on the expensive side because they are so small, but I love their art: https://vissevasse.com/

Grafika (France again) is a very mixed bag because it has a huge variety of artists. I'm mostly mentioning it because Josephine Wall might hit your style, her art has that dreamy vibe, but your examples are a lot cleaner and less busy and lighter, so I really don't know, but check her out. And, actually, Japanese painter Hokusai might also be your style, they have a couple of his prints. https://www.grafika-puzzle.com/

But honestly, style is so hard to nail down, you might just want to go to a site like https://www.puzzlemania.eu/ and do the leg work yourself. Go through the brands they have, google each one (the majority are European, I'm sure), so you know which ones to avoid, and then check out all their puzzles for styles you like. A lot of great puzzle manufacturers are in Europe, so I bet there is a lot of overlap between those you like, and those who manufacture in Europe.

Do you have other suggestions?