Lightest and most compact option I've found is a 2 ton scissor jack with adapter to fit an impact driver plus a couple short pieces of 2x6 cribbing. I have a Milwaukee M18. It raises the vehicle fast.
Without knowing what the failure mode was, it's hard to say if it was the derailler or user error. Did they start with low batteries? The AXS derailleurs are more reliable in some ways because of the internal clutch/auto adjust when taking a hit.
Rock n Roll Gold is probably the easiest for your use case. Squirt it on and use the solvents as a cleaner to get the drivetrain clean with a rag. Then let it sit for a couple of hours to dry. Before the invention of waxing, it was a top lube. Currently I wax with Molten Speed Wax which is the...