I obviously know nothing about your business but this sounds like a mistake from an outsider's perspective. Enterprise software exists so companies can call somebody and get help when something goes wrong. Also more people are familiar with Windows and Microsoft Office so it's much easier to onboard new employees and find IT Administrators who can support their environment and keep things running smoothly.
I think the setup you're describing will cost more in the long run because your company will have to find people with more specialized knowledge to help maintain everything.
I love Linux and open source software but I also think they should only be used when they fit the need.
We're going to buy the enterprise support plans for Nextcloud and Proxmox. I understand that some specialized knowledge would be needed, but we're making guides for it where anyone can do it (guides for flashing Coreboot, setting up Nextcloud, etc., this will be a guide for my boss for him to look back on). We will test this through slowly and try to see if this is something we can realistically do or not.
