Menubar + menu font size with Qt6

I know this question has been asked before, but there doesn’t seem to be a definitive answer in this list.

I am using TeXmacs 2.1.5 with Qt6. The font size of the menubar and of the menu items is too small for me. TeXmacs does not obey the “global” Qt6 settings (this was also the case with Qt5), so that method is out.
The Qt5 version had “High resolution settings”, which worked for me. But the Qt6 version doesn’t have this.

I tried setting “Interface scaling” to 2. That does scale the whole UI. But there are two issues. 1) The resulting size is too big, maybe 1.4 would be better. 2) TeXmacs gets a segmentation fault a couple of seconds after it comes up.

Does anyone have other ideas?

(My TeXmacs is built from SVN 15750 on FreeBSD)