Can I get some specific advice on how to handle the rushdown or platform game in situations from the videos?
I was trying to land upsmashes based on hard reads but eventually he just started waiting for them and I didn't adapt quick enough to figure out what I should be doing, I think one of my biggest problems is I just dont know what the correct options are in a lot of real situations, the stuff I do works on players who are worse than me but its difficult for me to improve without good practice partners.
I think you have the right idea. The thing is that up-smash/u-tilt are rather big commitments; you can't just throw them out and hope they will hit because they are so slow/laggy (not saying you're doing this as it's obvious that you do not). The first hitbox of up-smash appears on frame 14(-18) and have a ton of lag, while the first hitbox of comes appears on 8(-26) but covers less space and you can't do it OoS. It has a lot of lag afterwards too. This means you have to do absolutely sure that those moves will connect when using them, otherwise you get punished. However, being able to know what you opponent is about to do all the time isn't really realistic, so you have to guess or make hard reads from time to time.
Now, you probably know all this. My point is that you maybe should use less up-smash/u-tilt in neutral position/ when you're getting platform camped, and use more SH uair. Take a look at the frame data and hitboxes here:
Up-air
Total: 39
Hit: 6-23
IASA: 30
Auto cancel: <5 27>
Landlag: 32
Lcanceled: 16
U-tilt
Total: 49
Hit: 8-9, 11-12, 14-15, 17-18, 20-21,
23-24, 26
IASA: 42
Up-smash
Total: 49
Hit: 14-18
IASA: 44
Charge frame: 8
Alright, so uair is less laggy compered to up-smash/u-tilt and can even be auto cancelled after frame 27. The hitbox comes out really fast (frame 6+3=9, as you have to be in the air first) and is out for over 60% of the entire animation where the hitboxes of up-smash/u-tilt only last around 5-20% of their animations. You can do uair OoS and you can do it out of a running short hop making the move cover a lot of space because of the long lasting hitboxes. When connecting, it also hits as hard as up-smash/u-tilt in most situations and has great combo value because it isn't laggy.
Also, SH uair reaches higher than up-smash/u-tilt and can poke through the platforms of PS/YS/BF/FoD. In your matches there where a few times were you did a u-tilt under a platform while the other player was right above you. However, the hitbox of u-tilt didn't reach so the other player could just wait for the hitboxes to disappear and punish while you where in lag. With uair he will have to do something as he will be hit otherwise, and if he goes down through the platform you'll still get your hard read.
However, in order to make uair a great move, is has to be auto cancelled. The landinglag of the move is horrible, even when l-cancelled. This can be tricky, however, as you have to input the uair just as you leave the ground when short hopping if you want the auto cancel. You cab't fast fall either. The input window is rather small so this can take some time to get used to, especially if you use the c-stick for your aerials. I do all of my SH aerials with A+control stick because it's really hard to reach "up" on the c-stick in time in order to do a short hop auto cancelled uair. At this point I'm pretty much used to do aerials this way, but if you're not it can be trick as you might press "up" too much on the control stick making the sh uair a double jump uair which is bad.
TL;DR -
Auto cancelled short hop up air is better than up-smash/u-tilt is a lot of situations as it is faster, covers more space, is less laggy (when auto cancelled), and hits about as hard with great combo value. The timing can be tricky, however, especially with the c-stick, but it's a wonderful anti-platform-camping tool and not as risky to use as up-smash/u-tilt for hard reads. I've had great success with this move so far.