Loading QGIS external processing tools into Python environment

I’m looking to run some QGIS algorithms in a separate python environment (not the one built in to QGIS) and would like to use some externally provided processing tools (ie. FUSION, LAStools, UMEP etc). I’ve been able to get an environment working (I’m using Python 3 in Spyder through Anaconda, and QGIS 3.16) and can access the built in processing tools, but can’t figure out how to add these additional tools.

Thoughts?