My CPA was doing a great job filing, but she wasn't helping us plan for the future or giving me guidance on how to reduce my taxable income.I recently hired a new CPA that works with a lot of real estate investors and she's been great!

Sounds like you have too little free time and are getting burned out.If that's the case, hire a PMC!

In the end, I would have been better off hiring a GC to deal with all of the headaches, however I learned a ton by doing it on my own.

I decided to hire a full-time maintenance staff which is definitely helped reduce costs and avoid the issue With unreliable , bad work.

If you can time the market 55% of the time, I'll hire you as my financial advisor, we can both get rich trading stock options!

I'm at 64 units now but I hired third party management.

How should I approach the seller(direct mail or hire agent)?

If it’s not urgent then it can wait a day or two for one of your schedules to align which is what we have to deal with when we self manage vs hiring it out so that either you or the tenant is home

If landlord had to pay $1000 to advertise the unit or hire an agent to get it rented, the original tenant is off the hook for these costs.

I don't know what your background is @Zee Ayezain but if they don't want to sell it to you with owner financing as @John Underwood suggested I would recommend to them they hire a property manager.