The 3 main things Im noticing are:
1. You are pretty good at catching bananas quickly with aerials, but I didn't see a lot of Z catches or pickups before you landed. You open up a lot of options when you Z catch/pickup bananas. For example, say there is a banana right in front of you, and Diddy has one in his hand waiting to see what you do. You can pick up that one while rising and DJ above him, throw it straight down, and start pressuring him.
2. When you have a banana in hand, you don't always have to throw it offensively. Using them defensively is very strong. Say you grab a banana, and Diddy comes towards you. You think he will try to Fair you. So you Z drop the banana and airdodge behind it. Unless he times his Fair to catch the banana perfectly, he'll get hit instead and you can occasionally have positional advantage over him here.
Z dropping in general allows Wario a lot of Freedom. You can Z drop and recatch with an aerial, you can Z drop and recatch with an airdodge, you can just let it drop while you DJ/Position better, etc. I use that option a lot more whenever I play Gnes than throwing it away/at him, because he tends to play fast enough to react properly whenever I throw them directly. So I tend to play a bit more passive with bananas in hand, and wait for him to get impatient and try to Fair or approach me.
3. You had some trouble recovering. Against Diddy, I'd try to recover as high as possible as soon as possible to avoid his edgeguards. There's just too much risk trying to recover mid level or below usually.
Other than that, I'd suggest being a little more patient on your offensive strikes. I saw a bunch of times you would get a banana, throw it, and immediately go into your aerial and it would get beat out by Gnes rolling or using a quick counter attack. I'd go in and throw it, and get really close, but save your attack for when he makes a move. If you go in and do that, he fairs, you airdodge, BAM you get a free fart or Fsmash or grab or whatever.