Gas defo does not need (much) maintenance. Once set correctly, it can be fine for years, except cleaning ofc. Nitro, indeed, does require maintenance but that's a big part of the hobby. Imo I enjoy working on them.
"plus they still need a battery for the servo and stuff"- What hobby-grade...
If the backplate can hold a pullstarter (if it has four holes where screws can be screwed in), the cheapest option will probably be to get one. Note that most of the pullstarters have these screw holes 27mm out of eachother, while the vintage ones sometimes have a bigger backplate with 32mm...