It seems like an implementation issue of the interpreter no? There’s no reason lambdas _have_ to be this way.

lambdas don't have names, how could the interpreter possibly improve in this regard?

JS arrow functions don't have names either, it's inferred from the left hand side variable name. Can't Python do something similar?

If you assign a lambda to a variable, you might as well use a def. A more typical use of a lambda is as an arguments to a function call. What would be the name of, say, the first argument to map(lambda x: x*2, numbers)?