Headphone + dac amp

Thanks!
With my budget, 250/300€ for headphones which pair could I get? (Even 350/370€ if amp isn’t needed)
It would be a significant upgrade over the 990s, right?
[If needed] what dac/amp (or only amp) can i buy for 100€ or less?

What’s your preferred sound signature? What kinds of music do you enjoy?

I don’t know, and everything.
It’s like my first pair of good headphones so i still don’t know what i like, but i think something with a good soundstage and with accentuated drums [bass boost (?)].
So not a boring sound, i don’t think i explained myself well but as i said i don’t know really what i’m looking for, since i never tried good headphones before.