No, D-Tools will not affect your QuickBooks account in any ways you don't ask it to. We know your accounting is precious, and the last thing we want to do is mess it up.
D-Tools Cloud only allows for pushing Estimates from Projects, not invoices. If you send an estimate you didn't mean to or later decide you don't want to use, you will never have shown the client and you will be able to delete the estimate in QuickBooks without breaking anything in your accounting software. If you are happy with the estimate, you can turn that estimate into an invoice in QuickBooks online.
Accounts and Products you are pushing to QuickBooks will only be pushed when you do so. It will not affect any products in existing estimates and invoices and will only affect products in future estimates.