Thanks for the update.
The big box hardware stores often have R25 unfaced fiberglass batts on sale. I think our 1000 square foot home took 30ish bundles. There isn't anything fun about rolling out fiberglass in a 130+ degree attic though. Sealing all the wire,plumbing and duct penetrations is an important step before laying the insulation. Payback takes a long time so if you have to foot the bill it's not going to pay off in a rental home unless you plan on dealing with that landlord for another 10 years.