If python is too big for you and you’re dealing with heterogeneous systems then you’re probably stuck with sh as the lowest common denominator between those systems. I’m not aware of any scripting languages that are so portable you can simply install them with one file over scp.
Alternate route is to abandon a scripting interpreter completely and compile a static binary in something like Go and deploy the binary.
There was also some “compile to bash” programming languages that I’ve sneered at because I couldn’t think of a use case but this might be one.