Bold font fallback doesn't account for all fonts

This is an issue I have reports about from end users for quite a long time and is reported by end users using Windows, various Linux distributions and macOS. Personally I was unable to reproduce this for a long time, apparently it's highly dependent on which fonts the user has installed and my systems always seem to have the ones which compatible with Qt. But it seems this is 100% reproducible with out-of the-box Ubuntu 23.04.

Steps to reproduce:
1. Install Ubuntu 23.04
2. Launch the attached reproducer on it

Expected result: text is displayed with both regular and bold styles
Actual result:

This is likely related to QTBUG-99434 and QTBUG-102094 (yes, this is also reproducible with a string using mathematical symbols like 𝙷𝚊𝚝).