I've watched people play little mac online so much, and in tournaments (mainly the local ones, if I see a random little mac (which is rarely ever btw, so it usually draws me in), ill watch how he plays), and in all honesty, there's so many different things these guys do wrong in recoveries.
1. Don't at all do the exact same recovery all the time, (basically, recover low or high when the situation calls for it) this just makes you obvious and the opponent can easily read what you'll do next since your recovery is somewhat predictable by default.
2. Please, don't just side b right off the bat, it doesn't help, and if you saved your jump, you can easily mix it up and bait your opponent into making a mistake off stage.
3. My biggest pet peeve is when someone doesn't actually use one of (in my opinion) little mac's blessings in this game. Directional Airdodging is so good for him, it gives him another recovery option, and it can also very easily bait your opponent. Not many people play vs him, if you use this to your advantage, you can fake out what they think is a read, with directional airdodging and punish them a lot harder.
I've played him since 4, and in all honesty, he's been so much fun. Recovery is something I've gotten so good at, that even if they throw me off, it doesn't phase me. I just really wish one day they'll actually allow him to Side-B even after getting hit off stage, that's my only suggestion to fixing Little Mac, and honestly it could help a lot more than people may think. Even if you outplay your opponent, one simple read (which isn't hard) can cost your stock, so enabling us this would literally help recovery for everyone who plays him, not just Little Mac mains.
(Btw, I know this is all basic, but for anyone who is new to him, it may help? I just thought it'd be nice to share this stuff.)