counting breaks

I suggest deleting 00:06:542 (6,7) - and 00:08:015 (9,10) - for more simplicity and consistency, you only mapped piano at the start so you should stick with it, also 3/4 might confuse beginner level players

00:09:117 - would put there a not bcs it is a pretty loud sound and would put the blue note on the next white tick like this maybe: https://osu.ppy.sh/ss/17746103/2266

00:12:869 - could def fit a D here
this small section is kinda inconsistent with the rest of the set with this weird break here. Just my opinion

I would suggest keeping your structure from earlier on 00:17:833, I don't see a point in breaking it since it feels nice for a kantan and the music basically stays the same. So i would move 00:18:158 -> 00:18:320 and delete 00:18:482.

00:19:779 (13) - delete this note to make a required 3/1 break

would personally map something at 00:28:536 - to emphasize the finisher impacts w/ 3/1 breaks, feels a bit empty in comaprason here

00:30:482 (38) - I think this note would work well as a finisher, there is a strong sound here and it will show that the song is getting more intense

00:40:860 (68,69,70,71,72,73,74) - not a fan of this long pattern, I think it would be nice if you deleted the d after the finisher so it would be easier to play for the beginners

same here 01:17:185 (145,146,147,148,149,150,151) -

I would delete 00:50:185 to keep it consistent with ~ 00:55:293 (you didn't map 2 notes here like you did on 50:185). I would generally advise to avoid notes like that in a kantan since beginner players might struggle to randomly acc a snapping like that. Generally kantan players are used to only following the basic instrumental rhythm and important vocals .

00:58:374 (104,105,106) - Change to kdk, It's more comfortable to play and consistency

How about making 01:12:969 a k k d intead of a k d k, the triplet before and after this one are also both k d k and since the one after that is d d k it would be nice to have some variety here with something like a k k d, it also fits well in my opinion.

would put a note 01:20:752 d and 01:21:401 k

Perhaps it would be better if you moved 01:21:725 (152,153) -> 01:21:401 (152,153) and moved sv with it since those 3 sounds are very similar and if you have to pick a place within those 5 sounds to not put a note I would suggest going for 01:22:050.

01:21:726 (151) - This note is unsnapped, sv this effects it since it's unsnapped by +1 but would be nice to get out of the way :)

Maybe you can dkd on 01:28:536 instead of having a kkd twice in a row, would be more engaging for the player in my opinion especially in a kantan.

I think you would be better off moving 01:38:914 -> 01:38:590 to not break your structure there to keep rhythm consistency.