Most of the equipment & software I work with is owned/licensed by Honeywell and is proprietary, aka pricey. Older equipment can be found on reseller sites, but the developer software is expensive to license & hard to come by outside of the HON ecosystem.

If you go down the rabbit hole, check out Tridium, aka Niagara AX. Most(all?) of the big controls platforms are built on the Niagara framework.

Also, maybe contact contractors of Johnson Controls, Carrier Controls, Novar Controls, etc for more pertinent info.