the best advice i can give you is how to find out what you did wrong. look at what you did and why it got you punished, look closely at it, and look closely at how the neutral game played out, look for patterns in your play that were caught on to and focus on what you can do in the neutral to remedy this. look at what was unsafe and why armada didn't have to respect that option due to the lack of mixups or predictability in those mixups. the best way to get better is always to figure it out yourself, there is always a reason why a top player is able to call you out on your approaches, and if you spend your own time looking at it i'm sure you can find how he was able to know.
punishes are self explanitory as how you can improve them, just look at them and think to yourself, "is there a better option i can take at any point here that could have potentially lead to a greater punish" but also to look at the patterns in a players DI and how you can slowly gain a understanding of what they fear you will do via conditioning and respond with a different move that can combo into another. unfortunately for pikachu of his aerial moves hit at the same angle, other than upair of course, to truly get int0 their head you have to make them respect your coverage of a option on the edge, if they are recovering you can run out and cover a option if possible to do so safely, even if you know the player will not be there, and in doing so you get it into the players head that they cannot recover using that option, using this you can increase the chances of you reading or getting a reactable recovery. this is most prominent if you manage to cover foxes side-b options above the ledge, but also cover a double jump via your recovery angles to possible eat up the jump. in doing these things you can force a player into a worse situation. it is important to remember when punishing that downair and strong hit nair have almost identical knockback and identical angles, only having a difference of about 2 base knockback, so it is important to remember to only use downair in a situation in which you need the hitbox's coverage or to change hitbox position. one of the most important things to remember is to set up false patterns and habits you preform, in a way to go purposefully for the bad option so that you are able to use the better option that will beat them trying to cover the bad option on a read of it, this is especially important int the neutral where the opponent can punish a bad WD forward easily on reaction, but sometimes even a WD back, if you adjust them to be accustomed to these options you can punish them on a read of when they will read, and if successful you then have access to a "bad" option in neutral that can be easily read and you can abuse it to the highest degree. when dash dancing it is important to vary you distance and what options you do during it to properly force your opponent to truly respect it. it is important that you pressure fox and never let him have any breathing room, upair can cover a jump over and put fox into a bad position, at the edge of the stage you have more options into edgaurding which is naturally where you would want to apply pressure to force them to, but whats important to remember is that at higher percentages the gimp is not necessarily your only option, at percents in which you can platform combo using the chaingrab staying in the middle is a better option if you believe you can get a grab, as you can rack up more percentage before the final kill upsmash or upthrow into edgaurd, so having control of the middle of the stage if you are confident in your punish game can sometimes be a better option then pressuring them to the ledge, in these situations they lack the option of a medium high platform to run to, and in order to maintain stage position at the same time, as a result of this if they want to escape the pressure you can apply they either will give up stage position or doublejump to the top platform, in the situation where they doublejump you can have it lead to a lot of variance and combos via the situation they have put themselves in. holding position in the middle of the stage is in many even percent situations the better option if you can make your opponent respect your approaches, either way you end up getting stage position in the middle of the stage, and as stated earlier, this is where your combo chaingrabs and be the most effective in terms of damage output, so having the middle of the stage as your neutral games center at percentages where you cannot knock them off the edge using a move is a very good idea.
I still suck tho because I never take my own advice.
edit: when refering to the WD you have to remember that conditioning your opponent to thign all your WD will be a wd forward or backwards allows for you to wd in place and when they cover the WD forward you can punish them accordingly, unless they punish with a run up shine.