Way back in the day, the best browser was OmniWeb. It was truly awesome but quite expensive (I think a license was about $60?). Unfortunately they didn't have the resources to keep up as CSS/JavaScript became more complex. It still worked for the vast majority of websites when they gave up on development, but the writing was on the wall and they weren't selling enough licenses to hire a large team. Also back then the only open source browser was FireFox and it's always been a really complex rendering engine to work with (there's a reason everybody uses Blink or WebKit as the foundation for their browser).

As far as I know, OmniWeb is the only (major) browser that was exclusively designed for the Mac (and NeXT before that). Even Safari historically ran on Windows and the current version borrows quite a lot of UI conventions from the iOS version. OmniWeb was a proper Mac browser. In fact back in the early days of Mac OS X OmniWeb wasn't just the best Mac Browser, it was arguably the best Mac App in general. They'd been working on it for decades when other Mac apps were either brand Cocoa apps or else still using Carbon (the compatibility layer between MacOS 9 and MacOS X).

OmniWeb is kinda-sorta-alive as a side project, using WebKit now instead of their proprietary engine, and the latest "test build" was released just a couple months ago. But the last stable/officially supported version of OmniWeb 5 shipped twelve years ago. It's somewhat dated now, for example the URL bar is the full width of the window and you can't change that - a hold back from the days when even desktop computer screens were only 800 pixels wide or even less. https://omnistaging.omnigroup.com/omniweb/

One of the early developers of OmniWeb (retired a long time ago) once claimed OmniWeb is older than World Wide Web (generally recognised as the first ever web browser) but given the internet didn't exist back then he wasn't able to point to any strong evidence. Wikipedia lists 1995 as the release date for OmniWeb, however he said that date is wrong and it was distributed years earlier (obviously not on the web — there was no other web browser so you had to get it some other way).

These days, I think the best web browser (and therefore also the best Mac browser) is Arc. It's not exclusively a Mac app, but it is written in SwiftUI and the iOS/Windows versions are quite different - Arc respects platform specific UI conventions and different use cases (especially on a phone).

Hers's a link to download it: https://arc.net/gift/70d85b6 (unfortunately you do need to sign up with an email account, since Arc is "software as a service" and (like OmniWeb did) they eventually plan to start charging for certain features. I'm OK with that personally, you do need an account to sync tabs between devices which I see as a must have feature).