How to search/buy domain of my industry (dentistry)

"dentistry niche to offer services dental practices"; do you mean services to dental practices, so you are not yourself in an YMYL (Your Money or Your Life) niche? What services? Shouldn't you offer your services to them so that they don't have to find you? I don't think your money is well spent on an SEO domain, which is going to be expensive if it's any good (they are highly sought after), and even then the domain name itself can be awful, not good for branding.

Besides, the writing is on the wall, free traffic from search engines is dying. More and more ads before the first organic search result, AI tools replacing the need for a search engine, etc.