haha i can see why some ic's players say they do well against armada. i have never seen a strategy so simple and reductive. it's actually pretty suboptimal, but armada punishes better than any other peach off of one hit, so i can see why he still consistently wins the matchup. even if he doesn't use all of peach's good things vs ice climbers, like not using turnips or dairs to penetrate our defense, he has created a simple waiting strategy based on reactive fairs.
first of all, even though your movement in the neutral game is pretty good, the way you initiate offense is a little bit hasty. really try to pay attention to where armada is going, especially where he MIGHT go or where he CAN POTENTIALLY go. the best thing ic's have in this matchup is movement, and we have to move around and run away from peach a lot to maintain positions that aren't too risky.
what armada is doing is floating high and dominating the space below him and diagonally in front of him with the threat of fair. he isn't just throwing them out though, he's waiting to be in a good position before he uses it. then whether he hits your shield or gets a direct hit, he chooses a follow up based on that.
the fact that he's waiting can kinda be exploited. when we're not wavedashing or dash dancing to stay out of the fair's range, there are some opportunities to bite back. ic's generally don't have a lot of moves that can challenge that diagonal space, but if you think outside of the box there are some.
some options:
there were times where he floated too close and you could've hit him with a running short hopped nair before fair could even come out.
there were some times where he floated too low, and you could've done a short hopped synced ice block. this is good because there are like 4 hitboxes (two mallet, two projectiles) on the close ranged ice block, so there are many chances to clank with or beat whatever aerial peach does.
also, you can sometimes preemptively do a short hop synced side-B to make peach respect that air space. learn to control the aerial movement of the side-B to imitate a float, spinning like a helicopter horizontally. you can pepper some damage on peach and make her think twice about jumping into that space without thinking. you can kinda do it on reaction too, but the hitboxes are unreliable so i would only do it if i feel the peach is really not expecting it.
sometimes i wd in and utilt, ftilt upward, or usmash if i find her floating too low. usmash can kill but is so punishable that i really don't do it unless i really wanna go for an all-in KO gamble.
react and punish is generally the way to go vs peach... but if she knows how to make things safe, there are almost zero legitimate ways to punish her moves... i think that is the reason ic mains get so frustrated. so we have to find ways to initiate some offense ourselves... and theyre all so risky that i just gave up on the matchup lol. they also dont lead to grabs. lame!
anyway, these are some ways to deal with armada's reactive waiting and fair style peach. there are even better ways for her to fight ic's. the best at the matchup that i've fought were light, atma (they were more aggressive) and pink shinobi (extreme camping).