Does it matter if I connect an antenna via SMA or not?
I would be skipping the 50 ohms of resistance the SMA connector provides
There is no 50 ohms in that SMA connector, instead it has a 50 ohm characteristic impedance and that is something different.
You can just leave out the SMA connector and solder your antenna wire onto the board. A SMA connector with a proper antenna might give better performance but your wire solution will also work.