When I tried
curl --head on your desktop page (URL in your screenshot), your server returns a
308 (permanent redirect) to the
The desktop version of the URL that you are checking on Search Console is without
Google has no idea about what content could have existed in non-
www page (if at all) before you placed a redirect to the
www page. Hence, the redirect will be treated as a one to non-equivalent page. Thus you are receiving a soft 404.
Note: Why don't you have a single sitemap, thus making things easier for Google.
In the search console, just make sure that your property is (or includes)
www version of your website. While checking URLs in the inspection bar, you would be checking
www. prefixed ones.
In sitemaps, update all desktop URLs with
Regarding sitemap location, one in the desktop folder alone will be sufficient. (For details, please check the reference URL I have posted above)
In addition to the
www issue (please check the first part of this answer), there seem to be more problems. Now soft 404 is thrown for the
www version (where technically a 200 is returned). .
Here are my observations: (These points should apply to the mobile version's soft 404 issues as well)
Google can treat pages with minimal elements/content as soft 404s. Reference: https://developers.google.com/search/docs/advanced/crawling/soft-404-errors#pageother
Either you can wait or turn your implementation server-side (the most preferable solution in my view). Based on what I read, Next JS supports SSR - Server Side Rendering.
Though I know Google takes a lot of time to process client-side rendered pages, I am unaware of whether Google will go to the extreme of treating the pages with minimal content at the initial crawl as soft 404s till its rendering process is complete. But from your case, it looks likely. If you have the same doubt, you may post that as a separate question (important if you stick with client-side rendering).