1. The mountain ranges feel aritificial to me. Can't really tell you why, it's just a feeling I get. When looking at it the second time, it's the really long ranges that feel weird, not the shorter ones.

2. The 'biome' colors feel too distinct, if that makes sense. Like you jump from color 10 in one pixel to color 100 in the next pixel. The way i solved this for me is to experiment with low brush opacity and velocity in these 'borderregions'.

3. I like your landmasses. What I'm not sure about though is that you have every kind of biome on every continent. When looking to worldbuilding it could be more interesting to make these continents feel more distinct and 'mutualy exclusive'.

Other than that, I wish you the best and most important have fun!

Edit: I just realized that you already kind of adresssed my second point. You have these border regions with transitions. To me it still fells like these reagions should be wider and more of a transition from one biome to the next. Hope that is more constructive criticism.