Usually poor lead quality from website converts are due to misaligned messaging of the product, and also almost 0 friction in the web funnel.
Adding some picklists to prequalify, ie make the prospect do SOME work in order to book, will eliminate a lot of tire kickers.
When's the last time you did a review of your marketing messaging & sales messaging, chances are they're saying different things
Edit: When someone books on thru the website, they should feel like the messaging is written directly to them (are they ICP fit) and they understand when the right TIME to book is. IE if they're too early to get value from the product etc.