I once used Ghidra to decompile a hand-written ARM assembly floating point library and compile the result to a different architecture, and it was significantly faster than GCC’s built in methods…
But in general this kind of thing is very unreliable for any non-trivial code without a lot of manual work, so a better approach could be to compile to WebAssembly which can be translated into C
It may be easier if you also have the original source file (I've not don't much decompilation myself, only seen other people doing it), as more of a custom solution rather than using an existing system