So this is what I want to do and then build my own systems/sales team.Any advice or experience is appreciated.

After that, they have and control your money. 

Every system you try will have flaws, or you may salivate over a feature that appears in other software.Some familiar names are mentioned frequently: Stessa, Apartments.com, RentRedi, TenantCloud, Innago, RentManager, Avail, Rentec Direct, Doorloop, etc.I recommend conducting thorough research on each app online to understand their offerings, pricing, etc.

Once you're able to analyze the existing condition of these 6 systems, you can then source piece rate pricing from sub contractors or a GC -- this may be done by quantity, day rate, etc.

Infinite system and money created.Keep some dry powder for the emergencies.To Your Success!

I also use OpenPhone for my phone systems, and I love it.

What strategies or systems have helped you grow from your first project to a scalable operation while managing risks, timelines, and financing?

I want to develop a system where I can handle the maintenance and repairs through my phone without being there in person.

It is complicated because these investments are long-term, illiquid and completely out of your control.  

So that was my first partnership, we bought houses and I controlled the whole process and I learned so much.