Deadlifts aren’t a good source of lifting information because the grip area is unrealistically close to the centre of mass in comparison to practical things to lift, like engines. Even 20kg becomes very unwieldly when it’s in the form of a box that’s half a metre to a side.
Homophobe’s suggestion of having NPC’s to assist with lifting akin to assisting with crafting is a good idea. Maybe for the strength check, make the checked number actually the total of all strength scores nearby summed (like that video of a crowd tipping a train to free a passenger).
Even having just more than 1 person on a very bulky item can help, as it eliminates the need to also counteract the moment when lifting large heavy items.
Another thing we could look at is factoring in the volume when it comes to lifting things. Having the volume act as a lifting multiplier could work for vehicles, although I don’t know if you want this sort of snowflake code that only applies to vehicle item interactions.
We could also just increase the prevalence of items with lifting quality. Some sort of engine hoist should be pretty much guaranteed at every commercial garage. Although come to think of it, every car is supposed to have a jack and a spare as well, so I dunno, Perhaps all that stuff got teleported to ‘china’.