First of all, this is without a doubt a very well polished and fun game! Since you're probably here for constructive feedback, I'll focus a bit on the things that can still be improved, but just be aware that those are mostly nitpicks and most of what you've done already works very well.
To answer your last question first, no, I personally probably wouldn't play this with ad support on mobile, but that's mostly because I'm just not a huge fan of mobile gaming in general and it's also not quite my genre, so don't give too much on that. It definitely has enough quality that I could imagine it doing pretty well on mobile platforms. Just be sure not to overdo the ads and have an option to remove them entirely for a small fee.
(I kinda wish more mobile games would just charge up front, but I know that's not how the market works. Possibly one of the reasons why I dislike it as much as I do)
I have only one big complaint with the main game mode, which is that cannons shooting from the bottom obscure one of the dice down there. I often found myself rejuggling a die because I didn't remember what I was aiming for, and frankly, that's also not something I should be expected to do in this sort of game.
Other than that, this mode feels very nice! There were a few difficulty spikes whenever there were five dice to juggle, but those are fine. It's a bit annoying that the difficulty of those levels depend so much on whether you manage to get good rolls on your first swipe. I know I can influence those a bit in theory, but let's be honest, most people will just do a diagonal up swipe into one of the buckets here.
Also, maybe this mode is a bit short, but I'm not sure what's the best way to add more levels while staying varied. Maybe you can think of a couple more game elements you can add?
The new modes feel a lot like an afterthought. Practice mode just feels very weird and quickly slapped together. I'd like to be able to adjust the number and type of dice, toggle cannons, and so on for some actual practice. Maybe a simple solution would just be to use the default levels, but remove the win / loss conditions.
Endless mode feels like it could be fun, but boy, even at the very start it's just so much more difficult then the main mode! I'm not sure if there is such a thing as I only managed to get a score of 9, but if not, this definitely needs some sort of difficulty progression. Simple suggestion: Start with dice coming out very slowly and increase this rate continuously until theres more or less one constant stream of dice in the end. Also, maybe turn on inverted dice and cannons after certain score thresholds.
EDIT: Oh, and one more thing concerning endless mode, I'm pretty sure I would prefer if solved dice would be replaced immediately. Would also help lower the difficulty a bit.
UI, as well as generally the look and feel of the game are very nice. One suggestion I have here would be to add an outline shader to your 3D scene, which I think would help the 3D objects blend in better with the rest of the cartoonish style. Never tried implementing one myself and I've never used Unity, but here's a tutorial that seems to implement something similar: https://roystan.net/articles/outline-shader
Sound design is generally very nice, though I think the cannon shots could have a slightly more impactful sound. Music feels very synthetic, maybe there are versions of the music out there that feel a little more natural? I think I would prefer those.
Anyway, as mentioned in the beginning, these are mostly nitpicks. Overall, this is a very polished and professional-looking game, very well done!