Air carrier Captain reported the poor visibility and lack of proper lighting; signage; and ground markings made taxiing to the gate at EWR confusing.

Narrative

We landed in EWR at approximately XA:30 local time on the evening. The weather conditions were heavy rain; which was contributing to reduced visibility. We vacated Runway 22L on Taxiway N; and our instruction after crossing 22R was to join A10. The lighting situation on the ramp surrounding the A gates is grossly inadequate; which had been briefed as a threat. My FO called Ramp and reported that we were on A10 for Gate XX. Our instruction was to join Taxiway F3 for A9. As we approached F3 there were green taxiway lights veering to the left; albeit incomplete lighting as it terminated after only three or four lights into the turn. The poor visibility combined with no lighting assistance going to the right caused some confusion; and I was left with the impression we were supposed to make a left on F3 for a gate reassignment. My FO expertly verbalized confusion as to why I was initiating a left-hand turn when Taxiway A9 was to our right. Well; there is no lighting or signage AT ALL to the right of the A10/F3 intersection; and with the reduced visibility there were no ground lines visible either. All we could really see was a black hole with the promise of construction work. Taxiing in that direction seemed like an improbable instruction and poor idea. The Ramp Controller queried why we were stopped; and my FO received clarification that we were indeed supposed to turn right onto F3 and join Taxiway A9; still assigned Gate XX. It was slow going as there was absolutely no visible ground guidance or signage; and the moving map on the Jepp app was our only real resource. As we approached the gate the situation did not improve. There were still no visible ground markings; and the ramp crew were positioned in a way that made interpreting the probable location of the J-line very difficult. We did park uneventfully; but the situation was made needlessly challenging by the intense black hole effect of that entire ramp area.