Apex Is Primarily a battle royal game

The game is balanced around Trios, this barely works with Duo games though Quad and Solo games are definitely not made for this kind of balance.

They've tried Solo's before, despite some players loving it, they've collected data.

That data indicated things for them to decide shutting it down, so It's most likely not going to return... ever.

Private matches are more reserved for tournaments, as it takes up server capacity.

If they decide to host private matches on the host computer, then it means players can develop cheats easier and other things become much easier to find out.

There are modded versions of Apex out there that can be used for games against friends... though I do not endorse playing on these clients.

It's not allowed to have such a client, therefore your account can be banned for having such client.