You can be connected to 20 Apex and 20 Elitefundtrading accounts on the same VPS. You don't need a 2nd VPS for that. But if you did want to get a 2nd VPS, then that works too and you can place 1 trade on one VPS or in TradingView, and it will copy to all 40 accounts.
Only Replikanto can copy trades between multiple VPS.
You don't need any charts open. Only thing that needs to be open on the VPS is NinjaTrader with the trade copier window, either Apex Copier or Replikanto if using 1 VPS. If using multiple VPS, then only Replikanto.