Search Arbitrage - Need help for scaling. Any advice?

I'm facing scaling issues and would appreciate any tips or ideas on achieving a more stable CPA. Here's my Facebook strategy: I begin with a low-budget campaign running from 12 AM to 5 PM, with a daily budget of $30 to $60. This campaign is designed to warm up the RPC. Despite the low RPC during this period, the CPA remains low, resulting in consistent profits even when running it 24/7 across all 20 verticals. However, the peak RPC time is from 8 AM to 5 PM. During these hours, I launch a high-budget campaign with 20+ ad sets, each set at $20, and a CPC of $0.3-$0.5. Surprisingly, despite the low CPC, my CPA significantly increases from 0.4-0.5 to 1 or 1.2. This leads to minimal profits in some verticals and, in some cases, losses. Any advice on scaling more stably would be greatly appreciated!

Can you help me do arbitrage successfully? I have got agency accounts with high credits, we can potentially JV.