It’s worth expanding on my comment now I have a few minutes. You can terminate solid core like this if it has some strain relief but not stranded!.
My favoured construction method is to take a Hammond box lid and screw a piece of blank FR4 single sided copper to the inside of it leaving enough space around the edges for any (proper) connectors you need. You can then drill out anything you need, usually BNC, SMA, DC jacks, FT capacitors and D connectors for me. You build the prototype on the FR4 board dead bug and use solid core or RG174 to wire up the connectors and lap solder them to the boards or components as required. This is done carefully with thought for weight distribution and to keep the total mass of the wires low. When it works the Hammond box is closed. If it needs to withstand vibration or moisture you build it into the bottom of the Hammond box and when done fill it with potting compound.