https://www.cnet.com/news/huawei-p30-pro-vs-galaxy-s10-plus-a-race-for-top-android-phone/

Mate 30 Pro: 6.47-inch OLED; 2,340x1,080 pixelsGalaxy S10 Plus: 6.4-inch OLED; 3,040x1,440 pixels

The screen sizes are pretty similar, but it's interesting to point out that the resolutions are not. The P30 Pro has a lower resolution covering a larger screen. That makes pixel density on the Galaxy S10 Plus higher -- 522 ppi compared to 398 ppi. That'd be shocking if it weren't for the fact that the S10 Plus uses a 2,280x1,080-pixel resolution right out of the box. It only gets sharper if you change it in the setting, and the majority of people don't. If you're one who would, then Samsung has the advantage here, in theory at least.