Just for some clarification, is CZ the same as a Frontline match but just accessed via manual arrival?
Frontline Solutions is simply a taxi service to get to and return from the CZ and can be entirely skipped. The only reason you need to use FS (assuming you own a ship) is to find out what intensity CZs are because Fdev forgot to let us see that in our own system maps (I asked them to change this in Alpha).
The CZs all exist in isolation of FS. In fact, some systems don't even have FS because they only have outposts and no planetary or starports.
Now, I'd love it if the game supported the option to "restart the battle", much like most FPS games work. But, you can simulate this by just relogging. It works, the batttle resets (it sometimes takes about 60s but it will reset, just be patient) and you hit Tab to select your side and off you go again. This worked for me and another player in Open. Both of us not teamed up, just existing in the same open instance of the CZ - every single time we reset, the CZ reset and we just kept on playing it. If you are teaming up with someone, just invite to teams again at the start (again, wish this wasn't necessary, but it works ok as a workaround).
There's a lot wrong with how Odyssey works but CZs, in my experience so far, do work OK with this method. Very reliably too.
Just make sure you park your ship outside of 300m otherwise it'll auto dismiss itself for being too close. Obviously, there's a risk there in open too. If it was a busy instance with lots of players then I'd have dimissed my ship anyway. Just recall it when you're ready to leave (and if you're worried about other players, just log into solo first then do it).