On my Ventoy key, I have a Linux Live distribution with a persistence file so that I don't lose my settings. It's handy to have this kind of tool for a lot of things.
When I need a particular font to use under linux (and therefore with ventoy) but can't find it already converted to pf2, I download the font in TTF and then convert it to pf2 under linux with the 'Mkfont' command.
For what you want to have, starting from a Dejavusans.ttf font, it should be possible to do it like that:
For 18 size:
grub-mkfont -o DejaVu_Sans_18.pf2 --size=18 DejaVuSans.ttf.
When I need a particular font to use under linux (and therefore with ventoy) but can't find it already converted to pf2, I download the font in TTF and then convert it to pf2 under linux with the 'Mkfont' command.
For what you want to have, starting from a Dejavusans.ttf font, it should be possible to do it like that:
For 18 size:
grub-mkfont -o DejaVu_Sans_18.pf2 --size=18 DejaVuSans.ttf.