Changes to CRM & Campaigns Sync

After finding out recently via the platform, as opposed to an email from Zoho, we have found out that we now have sync to all of our contacts to Campaigns from CRM,

Currently within the contacts module within the CRM, we have various types of customers that have opted in for communications and those that have not- we do not want those that haven’t opted in to be added into campaigns, is there a workaround for this in regards to the sync? (essentially we want to be able to selectively sync into Campaigns specific contacts from the contacts module – as opposed to all contacts)

could we have a flow that adds to a list instead and not have an active sync in place?

If this is not something we can do anymore, we would look at disabling the sync between campaigns, however we would still need access to historic campaigns for auditing reasons and also understand campaign performance within the CRM, will this still be in place for viewing?