Planning a trip here, thanks for all the pictures!
The NPS will be no help: they proposed a wilderness in the area of the historic Rincon road (see below). And in the future, if congress rejects/releases the area as wilderness, anti-access groups will say the road is unused and "reclaiming" because no one went on it for years, then NPS closes it permanently...

Looks like RS2477 is the only hope for legal access.
https://www.govinfo.gov/content/pkg/FR-2021-01-15/pdf/2020-28464.pdf
Comment: Several commenters
requested that the NPS designate a
historic route in the Rincon Area
leading to Lake Powell as open to motor
vehicles. These commenters stated that
this route has a precedent of motor
vehicle use and is identified on several
area maps as the only method of
accessing the lake from the Hole in the
Rock trail.
NPS Response: The Rincon Road is
located within a proposed wilderness
area. The Wilderness Act prohibits the
use of motor vehicles in wilderness
areas. 16 U.S.C. 1133(c). The NPS
manages proposed wilderness areas in a
manner that preserves the wilderness
character and will not diminish the
eligibility of such areas for designation.