This is really odd, and I’ve never seen it before.
If you search for “Jim’s Guides” the site I manage appears first page. For me it’s number three, might be different for you, but should still be first page.
If you search for “Jims Guides” the site is nowhere, at least not top fifteen.
I always understood Google didn’t differentiate things like this, so either they now do (weird!), or there is some deeper issue?
Oh, by the way, the site is https://www.guidebookspain.com/