I guess it depends how much money you have 
I remember seeing a good thread here on increasing trust score and general engagement rate.
What stood out was the low-cost promos that would be very good for a business just starting out. For example, in-app boosts of around £2/€2 a day to keep overall ER high.
With bigger budgets (£50-£300/month), you could pay a VA or agency to do F/UF. You’re also getting into M/S territory, but that depends on whether you want to set it up yourself or pay someone else to do it.
The problem with paid growth, is you need a fully costed method to get that money back. Without that, you’re gambling.