Text with certain glyphs causes text (e.g. in most visible elements of Quod Libet or in the status line of waybar) to suddenly take on lots of vertical space.
Thanks for checking! For experimentation I tried switching to the Fira family (depicted), though previously I was using Cantarell. It appears that neither of these actually support U+1d15f:
I forget how to change the fallback order but it is possible somehow. I am getting FreeFont as the fallback on my system and the spacing on that seems to be all right.
I did some cursory digging but decided against that. U&L SE suggests tinkering with the entries in /etc/fonts/conf.d, but I think that’s more than I would like to do.
Wild speculation: U+1D15F (among several other glyphs in the neighborhood) are really only meant for musical typesetting and not for more general usage. U+2669 (the first alternative you suggested) is much better-supported.