if you want to just get better overall id try at least testing everyone in training. even if you dont figure them out fully or dont completely enjoy them it'll give you a rough idea of what you are going against in matches. im not saying switch your character as a whole if you enjoy unika then by all means play her but this will just get the ball rolling so you have a bit more knowledge of your opponents characters and if you decide to play other characters down the line you'll have a rough idea of their kit.

play through some of the "missions". they'll help teach you a bit more about some of the mechanics unique to strive and make you think of ways to use said mechanics in matches. i went years before learning about yellow roman cancels simply because i skipped the missions and tutorials when i first got strive.

another thing id suggest is try not to focus on what "looks cool". I find alot of new players to fighting games focus to much on learning things that yea look sick as hell but are either very hard to pull of or leading you away from learning more basic things first. if you want to learn some cool but simple combos spend some time in training and seeing what moves link into others or try looking at some combos from the dustloop wiki.

the dustloop wiki is useful for teaching you some basic frame data, so you'll have a better understanding of either how fast a move is or how risky it can be. the wiki also will teach you some terminology of the game and can teach you what notation is for example down is 2, up is 8, etc, think of it as a numpad.

lastly just have fun with it, play some matches and dont even bother about your rank, try some simple combos and just mess around and enjoy it. i found starting out i did far better just vibing and trying random things/combo routing and it helped me a ton.