User281315223 posted
Blazor and your application will really be as SEO-friendly as you decide for it to be. Although it's a SPA, there are plenty of tools out there
like this free one from the folks at DevExpress, that is specifically to update all the SEO-specific metadata for your site at runtime.
Additionally, Blazor also supports server-side rendering, which would allow it to function just as any other common site would (and SEO would work accordingly).