Extension fixes this issue:
https://spectrum.chat/figma/feature-requests/zooming-speed-with-ctrl-mouse-scroll-on-firefox-differs-from-googles-chrome~250fac37-73e9-4319-b38a-297bf4db5843

It makes scroll in Linux faster for figma.com site.

Install

• License: MIT License
• Weekly downloads: 1
• Average daily users: 87
• Rating: 5/5 of 23 ratings
• Created: 2020-07-09 05:03:37
• Last updated: 2021-01-19 14:15:18
• Homepage: https://github.com/800147/scroll-figma
• Support site and email
• Orig: https://addons.mozilla.org/en-US/firefox/addon/scroll-figma/
• API: {348fb2e2-a40f-452b-96fe-a4b5c18cd0d8}