You should start with buying noKYC bitcoin. There's no way to "clean" KYC'D Bitcoin.

You can do things to improve your privacy on the base layer like coin joins, state chains, silent payments and pay join. Then there is liquid which can hide the amount transfered. There is the lightning network which doesn't leave a record on chain. And more recently there are ecash mints which give you an anonymity set of the users in that particular mint.

Keep learning and all the best!