They should focus on saving Firefox. - Cut out all (or at the very least, most) initiatives that don't serve the goal of promoting Firefox's market share or sustainability going forward - Donate the major money drains that aren't Firefox to the Apache Foundation or another worthy custodian - Fire all inessential staff that don't want to work on Firefox. - Get a CEO/upper management that are in it for the passion, not…
Microsoft, with their resource and their ability to bundle Microsoft Edge in with Windows, couldn't get any appreciable amount of marketshare. Firefox, with less resource than Microsoft, won't fare any better.
Rebuilding Firefox with Chronium would salvage whatever the mindshare/marketshare left. Then Firefox could still wield some influence with their marketshare and the threat of forking Chronium.