Decent mobile browsers have a 'Desktop View' setting, which uses the websites desktop display. I use sometimes, as some websites' components do not work properly on the mobile browsers setting.
Unless you wish to go along with what Microsoft or Google almost forces upon us, ask developer to test in Firefox Desktop and Mobile browsers, and also Internet Explorer & Edge. Edge is the new thing in W10. It is a long way from perfect. Many PC users like the fexibility of Browser addons to do different things (A biggie with Firefox) Probably the most universal browser all round at the moment.
I have the best of both worls, as my Android phone connects to a Dell 27" widescreen and dispays in HD exactly as phone screen, portrait or landscape.
I just use PC or laptop for YEM, etc.
Al 😊👍