Engines being a viable business is kind of questionable in 2024 and on. There are lots of free or very inexpensive options already out there with incredible documentation, tooling and asset store components available, so any new startup has to compete with those on cost and capability simultaneously.

If your goal is to build a viable business instead of just scam your investors, you probably either have to try and compete with Roblox by creating an ecosystem where you siphon revenue off of your customers and their customers simultaneously, or sell actual product (sort of like how Epic bankrolls their stuff using revenue from their games) alongside tools.