Ah. I was getting confused. So the least-verbose choices become, I think,
[-Mstrict] -Mfeature=:all -- - <<EOF to run a stdin script
[-Mstrict] -E script to run a stringified script
-Mv5.28 {-e script | -- -} (as of now) to require a recent perl with all security & unicode fixes, turn on strict, and run either a stdin or a stringified script.