Unfortunately we can not influence the choices that Safari makes, but we did pull an effort to build an entire browser [1] to replace it because of that :)
We haven't begun work on the Linux version of the browser yet. We will need to significantly expand our team before undertaking the development of a browser for a new platform.
The macOS browser is based on WebKit. If the team can’t justify the Linux version yet, changing it to a whole different engine (and one which is notoriously hard to embed, by admission of Mozilla itself) is even less likely.
Unfortunately we can not influence the choices that Safari makes, but we did pull an effort to build an entire browser [1] to replace it because of that :)
[1] https://browser.kagi.com