I always wonder why you would target another language with your compiler, instead of an IR.

What is the benefit of transpiling to C++ over using LLVM?

(not meant as a criticism, genuinely curious)

It is easier to deal with, going one step further requires dealing with more low level coding and can be demotivating for some.

However I would advise to target an IR instead.

Doesn't need to be LLVM, if the purpose is only learning about compilers, do as follows:

1 - Create an IR, preferably stack based as they are quite easy to target

2 - Basic IR interpreter for testing the workflow

3 - With a macro assembler, convert the IR into machine code in a dumb way

Now you have a workable compiler, even if it won't win any prizes.

If still interesting, then proceed to improve the code generation in a proper way.

Ribbit is an R4RS implementation that is extremely compact. The video is only 15 minutes and worth a watch.