The screen of my iphone xs max screen got scratch only a month after usage.

Please remember the latest models have an oleophobic (fingerprint resistant) coating layer on the screen, which is relatively soft compared with glass and is designed to wear away slowly with use. That means it tends to mark easily but the marks tend to smooth away after a little more use.

If you have really abused your iPhone and the scratch is deep enough to mark the glass the practical solution is a toughened glass screen protectors which will tend to hide the damage, and reduce the risk of more scratches. If a protector does get scratched it is also cheap and easy to replace.

Every iPhone since the 3GS has had an oleophobic coating. Although the composition of whatever chemistry they use has likely changed somewhat.

For people who carry their device with the display uncovered in their pocket or bag, complaints of scratches have always been posted. It only takes a grain or two of sand or some other hard material in your pocket to scratch a flat glass panel.

Thats the main reason I’ve been using Sena folio cases for years, so the display is covered when not in use. Never had a scratch on any of my iPhones (and I’ve never used a screen protector of any kind, just the case flap covering the screen when carried).

Yes, the folio cases are ideal, I'm using the Apple version right now. I also use a glass screen protector because I know my hands can get dirty while I'm working so the screen would be subject to more abrasive wear than usual. This one is a Belkin, the only problem is that some of my stylus tipped pens don't work on it so I have to be careful which one I grab to answer a call if I'm working in gloves.

It's glass and can scratch depending on what it's been exposed to. It happens.