Any way to speed up loading time of an icon?

[Beaterie]

When I open a e.g. a modal where one of these icons is displayed, often the modal opens and the icon is not ready. It loads and pops up after 1-2 seconds which can irritate overall look of the webpage.

Any ideas how to speed up the loading time or how to initiate a pre-render of the icon?

(Mark: I code the website as a pwa, so I want to let the page feel like a native app as best as possible.)

[Pentadome]

Client Bundle

[Beaterie]

Client Bundle

Thank you!