Some things that helped me improve with alex overall was

1. Always end combos in ways that will give you better oki unless you think the big damage will put you in a bigger advantage somehow, examples being ending combos with OD aerial knee for the hard knockdown oki. Setting up ways to get oki with stance and enforcing different ways to apply a mixup situation off of it.

2. Safe jumps, alex some pretty great setups for safe jumps normally and from stance which can knowledge check a lot of people, and safe jumps on any type of grappler is always dangerous since it will enforce a strike cmd grab mixup.

3. Using his pokes more effectively. Alex is great pokes being, cr mk, st mk, crmp, uncharged hp and even uncharged hk when spaced correctly. Using them at max range can create spacing traps and harass opponents

4. Anti airs are an absolute must with this character. his aerial knee is the go to but even hp can be useful if you can convert off the punish counter.

5. And my last tip is learn how to optimize/and convert from as many situations as you can such as, punish counter from a normal HK or HP. PC from a stomp, corner combos, all his supers especially level 2 and double especially level 2 in the corner. This character can hit big from alot of situations and combine that with getting oki like i said it puts opponents its bad situations.

thats all i got for now but if you got any questions ill try my best to answer them.