Under the generation settings and then under text settings there is a font selector. It reads all the fonts you have installed on your PC when the app loads. The size of the center symbol should be controlled by the symbol size setting (there was a bug in 1.0.0, but its fixed in v1.0.1)
So I get the same debug error on my laptop as my desktop via the debug: The specified value "#0000 does not conform to the required index.html:205 format. The format is "#rrggbb" where rr, gg, bb are two-digit hexadecimal numbers.
Curiously though, my desktop has slightly different specs than my laptop but the laptop CAN change fonts with no issue. Laptop specs are : AMD Ryzen 7 5800H 3.2 GHZ with 16 GB ram and Geforce RTX 3050 Laptop GPU
Desktop: Ryzen 7 3700 3.6 GHZ with 16 GB ram and Geforce 3060 GPU
I'm at work until tomorrow so I cannot get my DXDIAG for my desktop until then