Are you considering off the shelf designs like the Nabu-Casa green for each customers server? The profits are ploughed back into the HomeAssistant ecosystem.
What of the peripherals - will you be the sole supplier of devices that need IPV6 for Matter/Thread integration, and can configure a range of routers customers have to support it?
Will you provide support for those that buy cheap chinese junk with non-existent documentation, relying on a Tuya cloud, for which at least three integrations are commonly currently used in HomeAssistant?
Are you paying by the hour, or by project?
On site, or remote access for customer support and upgrades? VPNs? Automatic updates? Backups of each configuration to your cloud servers,
Will you be contributing your privately funded developments and tweaks back to Open Source, paying it forward?
Will you have a 24/7 help desk team for customers to call? Technically proficient, fluent Mexican speaking, without a foreign accent? Not an AI bot trained on outdated information.
Look at the HomeAssistant monthly updates aftermath, each and every month, commonly reported here on these forums in bulk. ZigBee devices gone missing, frozen greens stuck updating, broken dashboards, breaking changes that bork third party apps. Can you cope with that, given the support provided here is voluntary by most participants (like me), of varying experience and skill levels You won’t be steering your customers here as well as Discord when they have problems?
I wish you the best of success. With the right team behind you, and the right products, you can do it.