Mine are the same, a glossy red finish, I’ve thought about sanding them down with a 400/600 grit paper to take the glossy finish away, hopefully that’ll then help the paint stick easier.
I don’t want them matte white though so I’d also go over them with a gloss white after if I wasn’t happy with the finish the tile paint gives.
I’ll try and find a picture, let me know if you think white would go with my kitchen rather than red?
I quite like those tiles
looks okay to me