When snake is offstage, damage > kill. You go for dairs that often miss/send them up when a fair/nair/bair would hit them/send them back offstage again. Unless they're cyphering dumbly, don't try to spike them. Just keep them offstage.
Most of the time you try to usmash his landing, you get punished for it, do the NEO, shield and grab, or run behind and pivot grab his landing and uthrow him to reset the situation.
Hell, uthrow him more in general if a fthrow/dthrow won't get him offstage.
At low percents when you get a grab on him, you do fthrow -> Dancing Blade. While good, and will get him off stage a lot. There were times you grabbed him when you were on the opposite side of the stage. You can always get another grab off snake at 0 so instead do fthrow -> fthrow -> dancing blade.
Also at low percents, when you hit with uair, you always usmash. Instead, after the uair, nair him. It's a better follow up since at lower percents, you can usually get another grab or something else on him. So overall, more damage and it's likely you'll get him offstage.
You got hit by the last hit of his nair too much, work on SDIing that.
Also, when you know you're going to whiff a fair, retreat it, don't keep going forward. You did that in game one and got utilted for it.
And when you shield the first hit of his ftilt, you keep spot dodging the second hit, then dolphin slashing. Just dolphin slash immediately OOS after the first hit. Spot dodging gives him an opportunity to punish.