I haven’t tried this so I can’t vouch for it, but it looks like you can add custom domains to a whitelist per https://support.mozilla.org/en-US/questions/1292986
So in your case, something like
browser.fixup.domainsuffixwhitelist.work = true
may work.
100%. They’ve just guaranteed that the sous vide unit that I have now is the last Anova product I will ever buy.