OK. Thanks. I looked around and found this for what looks like your board: KS0319 keyestudio GPS Module - Keyestudio Wiki
In your case, the integrated "Patch" antenna is passive and there is an external RF amplifier (Max2659). The SMA socket is power fed from the Vcc-RF pin on the neo-7 module. The capacitor C2 simply isolates any RF signal derived from the patch antenna which, as the documentation points out, could cause a conflict with a signal via the SMA socket.
In the case of my module, any possible conflict is resolved by the user not installing simultaneously both an IPX antenna and an SMA antenna.
Any antenna (IPX or SMA connected) has to be active because there is no equivalent of the Max2659 RF amplifier as on your board.
The pin marked Vcc-RF on my "neo-M8n" simply does not produce any power, hence my "work around". I'm guessing that there is some mismatch between the "neo" module, the firmware that has been loaded into it and the board it has been soldered to.
Having modified it, the performance is quite good even indoors with the IPX patch antenna (my house is of wood construction). However, there is now no protection against any possible short circuit at the antenna.
You'll have noticed that there is a considerable price difference between the modules, I guess for a good reason.