I have synced dotfiles across my various machines and I run i3 across these. My configs for DPI consist entirely of the following:

Xresources:

    Xft.dpi:120
    st.font: monospace:size=14

xsession:

    # haven't had time to dig into this, some systems need
    # DPI set twice
    xSetDpi () { xrandr --dpi "$1"; xrandr --dpi "$1"; }

That function is called in a case statement for other machine-specific startup config, but it's just a matter of xSetDpi 144;.

emacs.d/init.el:

    (set-face-attribute 'default nil :height xxx)

Again this is per-host, but it's a simple COND expression.

qutebrowser/config.py:

    # even with DPI set, I typically find web text too small
    c.zoom.default = '175%'

I promise you that this does not feel like any significant effort for me. It's ~10 lines across a few config files, each of which I would be maintaining anyway - none of these configs were born for the express purpose of handling DPI or zoom or anything like that.

I value having a system that is configured exactly to my preferences. I recognize that having multiple configs is a turnoff for some. I can't debate personal preference.

I have spent much more time trying to get something like Gnome to behave in a way I want than I have on all of my current config. XFCE is a pretty good experience for a DE and configuring scaling through system settings.

Machines:

1. 11" HD, OpenBSD current

2. 12" FHD, Artix Linux

3. 2x27" WQHD, Artix Linux