self hosted font problems

hi there,

there was a similar topic some time ago, but unfortunately i wasnt able to recover it ...

so another one.
i am intending to host the used fonts in the website localy via @fontface and turn google fonts off. further one i want only the choosen font to show up as a selection in gp/customizer.
so far everythings working.

but: implementing it that way via child theme and custom css it gives me a FOUT (flash of unstyled text) upon pageload.
not that sexy.

trying the given option via elementor and uploading the custom font through elementor i have to turn off the option to respect the fonts given by the theme and then theres no fout surprisingly.
downside is: i am no longer able to define the font-settings via gp, and gp does not even show the custom font to select.

if i want to select the font settings via gp then i have to make elementor respect the font settings from theme and again having that annoying fout ...
letting elementor having (limited) control over the fonts theres no fout but gp does not recognize the font (unless i add it again via @fontface in custom css.

in other words: eighter way running into problems.

so the question is: is there a way to make gp recognize the custom font managed by elementor and avoid the FOUT??? and in addition being able to style all text in gp?

another question would be why there is that FOUT when applying the custom font in child theme of gp but not when adding it via elementor???
what does elementor different? (regardles that it uses @fontface obviously as well?)

any enlightment appreciated :)