I'll start recording my matches.
This morning it was Steve and Leo. Just no idea what they're doing.
I guess I'll start going through other people's movelists.
Steve is a pretty complex character but his major gameplan is to bait you into a counter hit since his launchers are super slow. The biggest weapon is his b+1, which is a high left hook that is a deadly counter hit launcher. Because it's high, when in doubt dick punch.
Other things to know is his stances: Flicker (FLK) and Peak-a-Boo (PAB).
FLK stance only leads to mids and highs so is meant to bait you into counterhits or set you up for something after the sequence rather than break your defense. PAB stance is one that has some dangerous strings that can break your defense with various high-low mixups and other launchers. Various moves off PAB are unsafe and can be punished so if you succeed in defending you will be rewarded.
Things get seriously convoluted when you factor in the fact that Steve and sway or duck at any point from both FLK and PAB that can usually do pretty well in evading quick pokes you may use to try and keep Steve honest. But at least everything out of sway is mid so you don't have to worry about a mixup and you get your turn again after their move. However if the Steve player calls you out on your defensive play, then can transition the sway into extended duck which leads to unblockables and heavy frame disadvantage situations. Learning the Steve matchup is indeed challenging and it comes with practice & experience. I too had to lose 100's of matches against him before gaining some confidence in fighting him.
As for Leo, the KNK stance is the ultimate beginner killer. Most Leo players will get into that stance by doing b+1,4 which is the shoulder into a knee that leads into the KNK stance. Common logic for 3D fighters say that when a character does a mid,mid string on you it should be either unsafe or at least your turn to attack. But in Leo's case she's actually +8 after that, so if you retaliate with any conventional poke you'll get counter hit. But this is where frame data and character knowledge plays a big role. She has 2 high follow ups that are both ~15 frames which will counter hit any retaliation, a low that's ~20 frames, and a mid launcher that's also ~20 frames. So going by that information, you should be able to decipher that a high crushing move that's 11 frames or faster should be able to beat out 3 of Leo's options from BOK stance. Hence, a dick punch which is 10 frames will beat 3 of those options each time consistently. You just have to watch out for the mid launcher but that's not something most Leo players will just throw out since it's punishable compared to the other moves.
That's just one tool Leo has, there are other things about the Leo matchup to consider but they at least follow the conventional ruleset applied to 3D fighting games.
If you have good reactions and your character has a strong Backswing-blow like Devil Jin's b+3, Bob's b,f+1, Law's b+3+4(?) then you can input the backswing blow in between the b+1,4 and you'll dodge the knee and get a guaranteed punish on Leo every time. Yeah, I too was terrorized by this move for a very long time (entirety of Tekken 6) until figuring it out.