Seems like it would be easy enough to make a simple stand.
Measure the desk space and your height and foot position sitting in the chair for your dimensions.
Use a square or rectangular base to put the pedals on. If your chair has wheels make two holes in the base to drop the wheels in so it won't slide back.
You need 4 legs to hold the stands.
Make a U shaped piece for the top. That's your stick/throttle shelves connected for stability. Make sure your knees have enough room when you use the pedals.
Add lateral support to the stand legs on 3 sides.
That should give you something like an open box you can put under your desk.
Of course I haven't seen your desk.
My old desk was a wood slab so it was easy to attach two shelves below it, offset with dowels, to mount a stick and throttle on either side of the chair.