hello! i havent really looked at the hard diff much but what i can say is that the easy and normal diffs are farrrr too difficult for their respective labels if you want to look at it from the perspective of ranking standards. i'll mostly focus on the easy as an example.
generally speaking for easy diffs, 1/4th patterns especially at this BPM is going to be much too difficult for newer players to properly play, usually easy diffs are made up of 1/1 patterns with occasional 1/2 patterns (emphasis on occasional) so even the general structure of the map wouldnt necessarily fit the "easy" description. another thing to note is having complex (or really even any note patterns at 180BPM) WITH LN holds would be a big no no for easy difficulties, i am talking about the section from 1:30:666 - 1:51:333.
one thing that you did do sorta right lol (whether it be intentional or not) is that on easy diffs, LNs should be generally held for a full beat (1/1) and there were only like 4? LNs i saw which would break that, buuutt speaking back on what i said previously, it wouldnt be a good idea to have multiple LN holds at the same time (referring to the slow sections) in an easy diff
what i would do personally is just to nerf this diff a bit to better fit the "normal" diff standards as labeled in the RC: https://osu.ppy.sh/wiki/en/Ranking_criteria/osu!mania
And then just create a new easy diff with some of the things i pointed out in mind (this means you should also probably look into the actual normal diff and also the hard diff to maybe relabel them as hard/insane and then rebalance it to fit those standards
yes i think the shields are good there, i feel pretty satisfied with the difficulty of this diff now because i let one of my friends that are newer to the game try this and he usually plays around this level and he found the map fun but also challenging
i'll definitely give the mods a thumbs up! sorry about that