Rebuilt A998 - No upshift/only 1st gear

With the selector in Reverse your gauge will read the maximum pressure that the pump can produce, regardless of the TV as reverse is unregulated pressure. The pump usually puts out pressure well in excess of 230 psi. But no circuit requires this much pressure to operate. This reverse test just tells you if the pump is half-way decent.Yours seems low, but not dead.
BTW, nice video! Good work.
The servos are popping nicely, and I can clearly hear the Fwd clutch, feeding it's air pressure back through the apply hole after you released the pressure. Besides, if it was bad, you wouldn't have any forward gears at all,including low. On the roadtest;when you backed off and it felt like the tranny hit neutral, this indicates that the tranny was trying to hit second, and momentarily responded to governor pressure, by releasing the low servo.So it points to the VB.
If you had the VB apart I have some ideas; in addition to what has already been posted.