Do you get paid for every proposal or quote you issue or for every deal you close?
The answer is the latter (or at least it should be). Then wouldn’t it make sense to only spend time proposing deals you have a reasonable chance to win?
Do this by conducting thorough qualification and discovery. Get the insights into what’s driving their decision, who’s involved and their needs and priorities, their ability to pay, alternatives they are considering, consequences of not acting (buying) at all, and other indicators if the deal is a good fit for you. Whether they’re willing to collaborate with you on navigating their buying process and developing a solution are other telling signs.
Sending proposals before you understand these things is simply sales malpractice AND only impedes you success (i.e. closing deals)!