Install Userscripts. It's free and open source.
Get Userscripts
Open it once after installing so it can create its folder.
Turn it on in Safari: Settings → Apps → Safari → Extensions → Userscripts. Switch it on and set All Websites to Allow.
If you don't allow all websites, Safari asks once on each newspaper. Tap Allow.
Install Duo Fit. Open this link in Safari, tap the extensions icon in the address bar, choose Userscripts, then tap Install.
Install Duo Fit
If you don't see Install: copy the script, open the Userscripts menu, tap + → New JS, paste it over the placeholder and save.
Copied
Or download it as a file. In Files, move it into the Userscripts folder (On My iPhone → Userscripts). Userscripts runs whatever is in that folder.
Download Duo Fit
That's it. Open any newspaper from the list and unfold the phone. Front pages become a picture grid, and stories lay out in two columns across the fold. Tap Duo ✓ on the right edge of the screen to switch it off for a site.