Yeah, you can screw up real bad when it comes to privacy.
In my experience users screw up their privacy precisely **because manual coin control** and that's why IMO manual coin control should be hidden by default.
Even if you are separating non-KYC with KYC wallets, you may just not want to tie 2 different addresses that are both non-KYC or KYC. So you are going to need coin control enabled, because I don't think anyone wants to have a separate wallet for each separate sub criteria after the main non-KYC/KYC criterion so you are better off just controlling your utxos manually before any transactions.
Separating non-KYC from KYC wallets is a sad solution. It means that your wallet does a poor job managing the knowledge about how hows what and how to minimize it. If your wallet doesn't allow you manage manage that then you will screw it up sooner or later.
Just click on the different utxos checkboxes until the amount fills the needed amount of BTC you want to sell and you are set, anything above that just goes into a new address as change as usual.
This is in most of the cases a very bad idea. It is very unlike that users know exactly all people or entities that can track each of their utxos.