while this is a normal phase I like to call "kitchen sink'ing" where you have a lot if ideas and you just keep stacking them - it ends being too much for too long.
the ideas tend to sound fine isolated but they lack meaningful impact because there is no contrast to make you appreciate it It would be like listening to 2 solid minutes of dubstep with no drops.... you can make a mediocre drop sound massive by having excellent setup, and you can rob a drop by having a weak setup.
likewise, no matter how much you add, it'll never "hit" unless you're conscious of setting it up for the contrast it needs.
try this, using a copy if your project as an example... take the original idea with percussion and guitar, milk that for 8 bars or so, as *little* as you need to add to make it interesting. Then set up 4 or 8 bars of empty space and insert the more developed section like 1:25ish.
think about the major components here, lots of piano, and lots of guitar and percussion. All 3 of these textures are "plucked" or percussive instruments... so have a break that contrasts before you bring the extra piano on top. Opposite of piano like pluck sounds would be smooth longs of any strings, brass, winds, or pads.
I'd personally say strings, because you go go soft, and still have brass/choir if you want to "bring out bigger guns" for the last iteration. you could add a small synth riser here if you feel like you need a little boost, but less is more that early in the song. Also try to pick note ranges that are above or below the main piano development you add at 1:25... maybe low pianissimo brass chords and a high mp violin section, or pianissimo chords with celli/bass and a solo violin - again, try to use the bare minimum, and no percussive articulations here - so that when you come back in with drums, piano. and guitar - they have maximum impact. I've had a hard time teaching myself this but less is more - and changing the musical ideas isn't a substitute for contrasting ideas, textures. rhythms - and efficiency of ideas being milked is one if the true masteries of the craft. Heck, Tchaikovsky's 6th has many motifs that are literally going up rundown a scale, just cleverly disguised and dressed.
oddly enough this gives me some melodic doom metal vibes... like morbydia.
And this is criticism mostly from a listener's perspective ofcourse - trying to *think* like a layman.