Hi,
Unfortunately, PhyloPhlAn expects to find the "usearch" command in the system path and to be the 5.2.32 version.
A solution could be to write a small bash script that will export the specific usearch version only when running the script, so you don't have to set usearch 5.2.32 always, solving your other dependency problem.
I attached a template of the bash script, you have to set the correct path to where you have usearch 5.2.32 in your system, make sure the command is "usearch", and make also sure that the "python" command in your system is executing Python2, otherwise change it to a python command that runs Python2.
Please, let me know if this solves your problem.
Many thanks,
Francesco