As a joiner I invariably use 2-pack fillers where a painted finish is involved, but they generally aren't suitable for clear finishes of any type
From time to time I mix acrylic artist paints with 2 pack filler. It does take longer to cure though.
When filling holes in tiles I use the StoneFill "clear" 2 pack filler with the artist paints.
https://www.tetrion.co.uk/product/professional-stonefil/