Does that actually work? Last time I tried Sway there was no way to let X11 apps scale themselves, something that was supported in KDE and in Hyprland.
Scaling works great using those environment variables or setting things with xrandr in X11/i3. I should probably try Wayland again sometime to see if it sucks any less .. but probably not this year because I'd rather get stuff done than trying to fix a stupid broken windowing system.