@Randall-And-Heather0 You have used the terms Inquiry and Request interchangeably. Do you understand the difference between them?
You never have to either pre-approve nor decline an Inquiry. All you have to do is message back the inquirer within 24 hours. That counts as responding. So never waste declines on inquiries.
Requests are different. You must either accept or decline within 24 hours. If the guest's messaging or anything else throws up red flags for you, or they are asking for things you don't provide or allow, try to explain to them why you can't accept the booking and encourage them to withdraw the request so they'll be able to look for another listing that suits their needs. If they withdraw the request within 24 hours, you won't need to decline it.
Many hosts get requests from newbie guests who don't "get it"- haven't bothered to read through the listing info, house rules, etc. You shouldn't necessarily dismiss these as automatic declines. Sometimes you have to work through things with newbies, explaining how it's important for them to read through everything, etc. Many will be open to learning- they just didn't realize how to book an Airbnb beyond clicking on "Book". If they are still clueless, or rude, that's when you want to use the decline button.