I am not a TEMU fan as most of the stuff seem to be poor quality copies of the real thing. And getting a cheap swivel plate is IMO asking for trouble. Even the better ones can have issues so god knows what a knockoff TEMO one is like!
I would say avoid like the plague and if anyone does get one, check it really well and see if you can break it - it needs to be able to withstand very high forces in a crash so if you can do it any damage before it is fitted, it should be binned!
It is very likely that you can get a swivel plate for your van and it is usually a simple job to adapt to suit the mounting positions.
something that should be considered - and more so if fitting on a drivers seat though - is the effect on the seat height. These can raise the seat by upto 3" and that can cause a problem with shorter legs reaching the pedals. Another possible issue is raising your eyeline above the window frame. which can be quite an annoyance.
FWIW, I fitted plates to my VW T4 and I removed them later due to the eye-level thing - and my partner had the same problem in the passenger seat despite being only around 5' 7" or so.
In my VW LT, I swapped the front cab seats for Ford Galaxy seats which have integral swivel plates, so no extra height involved and a very good solution (better than my swivels in my current Ducato)