Well if you got your asterisks handed to you by a samus spamming projectiles, you probably don't have great techskill. If you can get close to samus her life gets very hard. Being far away from her isn't the best idea. Without techskill, fox is just a character who can run very quickly into being combo'd forever. You need to work on movement and punishes.
I suggest getting good at the triangle of tech, shffl, wavedash, dash dance. These three techniques are the base of the pyramid of tech in smash. Everything is built on those. You should be able to make it from ledge to ledge on each stage without leaving your initial dash animation. You should be able to wavedash every time. You should be able to shffl nairs back and forth, changing direction at will. Just these skills alone will make you much more formidable. It should only take a few weeks starting from nowhere.
If you already can do these techniques, you should learn the drillshine grab/usmash. At first you'll always want to usmash, since it's a smash attack. But often a grab is safer and actually leads to more percent. And you should only be trying to waveshine characters with high friction and don't fall down like ganon, link, peach.
Also don't get stuck practicing that drillshine shield pressure stuff from 2010 because people know how to get out now.
If you can already do that, waveland. Waveland waveland waveland. And always fastfall while you're in the air.
This is the stuff you need just to survive as fox.
Samus is a weird matchup, but fox can do it. Just remember you can't really shine spike samus, so focus more on building percent and killing off the top. She's heavy, but floaty. So she still dies to usmash in a jiffy. uthrow doesn't seem like it gives much, but you have complete control over her positioning if you just jump up there. She'll have to run from you - she fears the uair. When she land, or if she throws out a desperate aerial, hit her.
Also it takes a bit of time for her to shoot projectiles, except charged b, ill get back to that. So since missles take forever to come out, if you're close to her she can't shoot you with missles cuz they're too slow ( as long as you attack ever ). And if she's got a charge b it's because you were dead, or you let her charge it. Don't let her charge it. Stay close to samus, you don't camp her.
Also you can just nair missles, so don't be lasering and then get hit by a missle, if you're lasering and a missle comes, shffl a nair into it.
The last thing I have to say about this matchup is watchout for cc downsmash. When you nair samus she will hold down on the control stick and spam down on the c stick and you will get downsmashed unless you wait to nair until super late, or you don't nair at all and just run up grab.
PS. Samus' grab is really slow, so it's not safe. Shield is your friend in this matchup for that reason. That doesn't mean spam shield, it means that you can hold it a half a second longer than other matchups, which is a lot. and you can do it more often. Make sure you can wavedash out of shield also.
Ok ok, I'm done. I hope you work on some of this.
