Amberlamps
Formerly known as Phuca
You are right in your assumptions. Any adaptor when used on high speed data cables is not wise practice. As the cable connector itself can cause signal reflections up and down the cable. It’s best to use only properly made properly engineered high frequency cables. Sadly I’m afraid I must say here It’s unwise to purchase those types expensively made by Fred in a shed who hasn’t a clue about good RF engineering signal practices but is still quite happy to stick on a fancy label and charge a very fancy price for his dubious goods.
24k carat gold cable’s and 13amp fuses not your thing I see.
What about platinum ?