Have half of BTC at hand. Want to find a way for better investment rotation to be done. So far invented such a scheme. The whole amount to be exchanged for any local currency.
My advice is don't do anything, don't rotate your bitcoin with anything.
Simply hold your bitcoin in a safe place that must be non-custodial (self-custodial) and open-source wallet.
Second: How to make sure I use "clean" BTC from source of exchange?
Use KYC exchanges if you are ok with KYC.
When you use non KYC exchanges, you will interact with more tainted coins but if you submit a withdrawal from the non KYC exchange, they broadcast it for you and you will possibly have more cleaner coins but chance of tainted actually exists.