I swear by these pigtails for strain relief on your quad. These properly anchor your antenna and securely connect to your VTX.
TBS UNIFY PRO 5G8 SMA PIGTAIL (U.FL)
A spare SMA pigtail for the TBS Unify PRO 5G8 and TBS Unify PRO 5G8 HV. U.FL connector that allows snap-on installation.