Ohhh ok! Let me see if I understand, the problem in not being able to use DSP is the lack of SPDIF in our cars, but you can connect via standard harness connection if you enable AMP option in the options. I was worried because of JstnBrdy's failure in installing his DSP unit but I guess he screwed up by only using the 10 + 6 pin harness instead of the full harness which I will explain below.
As far as the connection goes, I got that figured out thanks to our resident Android HU expert
Akuma147. Basically you need the HILUX version of the Joying harness. You can use that universal Toyota Joying harness you linked but you need to then buy the antenna adapter and the 28-pin harness and wire them both to the main harness. If you want backup camera and steering wheel controls you also need to wire a few more things in, but it is all explained to perfection on Akuma's master guide. You do not need an expensive SWC interface for steering wheel controls. If you buy the Joying harness the 10 + 6 pin harness is already included so no need for that.
AKUMA147's master guide
If you confirm the DSP should not be a problem then I'm gonna pull the trigger. All I want to say is, god I love this forum. You guys are so helpful. When I'm successful I will pay it forward and make a guide of my own, though Akuma's is already good enough. Thank you Soundman.