CBDC does not have effect on a cash. If they wanted, they would outlaw cash without CBDC and they could track money around in current sytem. If tracking money is a goal, they already can do it. They don't need CBDC for that.

Some EU countries are extremely low on cash transactions anyway and some are on their way to remove cash CBDC or not.

I must say again....i heard a lot of "they will" and "they could" scenarios and not a single one is something they can not do in current system.

Tracking, can

Programable money, can

Blocking you from spending, can

Setting arbitrary limits for whatever reason they want, can