I have had lots of problems with the scaling in my Phaser 3 games at the beginning. Like you, I was used to the luxury of the Phaser 2 Scale Manager  However, meanwhile I have figured out a way that worked perfectly so far in all of my games and on all platforms / browsers. My resizeApp() function also takes into account the DPI values of different mobile devices. I noticed that even if I keep the ratio correct, different DPI values can STILL mess up my scaling. Since I've taken this into a