Is it possible to preload or otherwise cache @font-face fonts, most likely with javascript, before the page loads so you don't get that ugly jump when the page finally does load?
Please refer to this updated answer: https://stackoverflow.com/a/46830425/4031815
I'm not aware of any current technique to avoid the flicker as the font loads, however you can minimize it by sending proper cache headers for your font and making sure that that request goes through as quickly as possible.