What @GoldenBird said is golden.
Seriously.
I know fomo myself, but start slow.
1 sub only for the first month.
Learn to feel the sub, to feel behavioral changes, mood swings etc.
Just How you react to a sub.
It doesn’t matter if you’re new to personality development, mental alchemy, or shadowwork, or if you’ve been working on yourself for decades.
SC subs work in their very distinctive way and you need first to learn how they feel while they work in you.
Do you have concrete goals that led you to SC?
Based on that we can recommend certain subs.
If you strive “just” to improve your life/personality in general, Ascension, Ascended Mogul, Genesis or Genesis:Mogul are good fits.
Especially Ascension has a very narrow range and is often pretty fast acting so you get a feeling for it.