You'd need to know what the burn rate is composed of: their engineering organisation might be less expensive than the marketing budget in a single major market.

If they cut ad spend and raise costs, then their growth story stops and other competitors have a window to move.

The go-to reading (at least a few years ago) for handling the difficulties of burn rate at a high-growth company is 'Mastering the Rockefeller Habits' by Verne Harnish, the chapter on cashflow. I think 'The hard thing about hard things' also talks about how this situation can kill your company if you're unlucky or unprepared