True or false? From the moment the borrower gets first pre-approval, borrower has ~18 days they are exempt from additional real estate hard inquiries?

Is it true that from the moment a borrower gets their first pre-approval, the borrower has 18 days to go get a ton more pre-approvals without additional hard inquiries? I am eligible for VA and I intend to use it, at least assuming whatever property I purchase is eligible for VA (I don't think commercial and/or vacant land and/or construction loans have VA versions...?)

I also live in a tri-state area, and I don't want to make this post too long, but I am concerned that I should get pre-approvals in multiple states, and it seems like most credit unions do pre-approve multiple states.

If yes, the 18 day window is real, does the 18 day period only apply to the same type of loan and/or the same instituion? Perhaps I want to get pre-approvals at one institution for one, two, three, and four-unit properties, and a pre-approval for vacant/habitable-building-less land, too. Is that five separate hard inquiries, or just one? Or two, because all the residential building mortgage pre-approvals can be packaged together, but the land pre-approval is separate?

If at bank/credit-union/mortgage broker X I get five pre-approvals, one for each of those five things: One unit residential, two-unit residential, three-unit residential, four-unit residential, vacant residential land,

And then at bank/credit-union/mortgage broker Y I get five more pre-approvals for those same things, do I only have one hard inquiry total as long as I do it all within fourteen days? Do I have five hard inquiries? Ten hard inquiries? Is it two or four because vacant land isn't an FHA/VA? Obviously, I want the best rate.

Unfortunately, as of recently, my TransUnion and Equifax scores have taken a dip from ~805 to ~740. I was pre-approved when I was a younger man making considerably less money. I initially got two-pre-approvals at one credit union for FHA single unit home and Embarrassingly, I didn't buy any property, although I did waste significant time exploring an opportunity, trying to figure out if I could turn a right of way into a driveway (turns out, old ass 16.5 foot wide right of ways that have vague descriptions are worthless) and how to deal with resource protection, and I learned a lot.

The other unfortunate thing I ran into, is the loan officer and/or credit union employees at the credit union that pre-approved me were not interested in educating me. She always made vague statements on what types of land they would pre-approve for a vacant land loan (I say vacant land, but it's all land without habitable structures. I do not know the correct term). I would say, what if it is zoned mixed-use? What if there is a garage on it? And they would say "well, if it's a commercial use building on a residential property, and/or commercial use building on a mixed use property, you are would need a commercial loan, it will not be eligible for a residential land loan". I would ask them to define what a commercial property is, and they could never ever define it, and clearly, they didn't appreciate my questions.

Thank you so much