Use a browser to go to ebay.com rather than using the eBay app. Scroll to the bottom of the page and you should see a link to switch between the mobile version and the classic version.
Or you can request the desktop site version of the page in the three-dot menu of most browsers.
If eBay browser links are opening in the eBay app, there is a setting you need to change to prevent that, depending on which operating system you are using.
