We don't have support to change toolchains freely yet. However, you might still be able to do it. I haven't tested myself and it's kind of "hackish" to pull off so it's not an official recommendation from ST to do this... BUT:
You could maybe change it in the PATH but that might be tricky since I believe we always put our own first but you might be able to override that.
Or you could try swap the toolchain in the plugin of the CubeIDE installation.
Once again, haven't tried myself and I don't recommend it but if you really want to try that's probably the ways you could do it.
Let me know if you gave it a try and how it worked out!
