Random updates since it has been a few months.
@couponvan, I believe the 26% tax credit got extended by a couple of more years. So you are in luck.
https://rules.house.gov/sites/democrats.rules.house.gov/files/BILLS-116HR133SA-RCP-116-68.pdf -> page 2448, section 148
@nereo, I intended to, but eventually copped out on your suggestion of DIY attic hatch because a very enticingly convenient alternative came along.
I had basically given up on the idea of insulation, and suddenly chanced upon a solution. I had a contractor (from one of the inner city *hoods of a nearby big city) over to give me some estimates for some unrelated stuff, and he turned out to be a really good salesman - not the hard-selling a*seholes kind, but the ones that listen, understand and suggest solutions.
My issue was that I can't fill up the attic with insulation, because then I will lose storage space. Doing under the roof-board insulation was useless because the attic space is not within the heat-envelope of the house and bringing it within the heat envelope is not feasible because you have the bathroom vents opening in the attic and you want it to be well-vented (which it is), and you want it that way to avoid any moisture build up.
This new guy suggested that he'll just leave a 3ft X 20ft space open for me in the middle of the attic to use as storage space, and put "R30 cross batt fiberglass insulation" everywhere else.
So he did that + the attic hatch for a net OOP cost of $95 for me. Rest of the cost ($3.1k) was allegedly funded by the insulation rebate from the CT state:
https://www.energizect.com/your-home/rebates-and-incentives.
This was done right before the cold spell. I am hoping I will see the difference in the gas bill next month.