Problem with integration of GRASS-Gis in creating a process for PyWPS

Hey everyone:) It’s possible that I have some kind of miss-conception in my head and just wanted to ask it here. I have a space-time-datacube in GRASS-Gis and now I’d like to create a process in PyWPS that lets me calculate some statistics for an index (e.g. the ndvi).
I do have a script and I can create the process and see it on localhost. However, when I send a request to the server I always get:

PS&identifier=sen2_index&version=1.0.0 HTTP/1.1" 200 -
127.0.0.1 - - [22/Jun/2020 16:58:14] "GET /favicon.ico HTTP/1.1" 404 -
Traceback (most recent call last):
  File "/usr/local/lib/python3.6/dist-packages/pywps/app/Process.py", line 236, in _run_process
    self._set_grass(wps_request)
  File "/usr/local/lib/python3.6/dist-packages/pywps/app/Process.py", line 362, in _set_grass
    from grass.script import core as grass
ModuleNotFoundError: No module named 'grass'
127.0.0.1 - - [22/Jun/2020 16:59:10] "GET /wps?request=Execute&service=WPS&identifier=sen2_index&version=1.0.0&datainputs=start=2019-07-01;end=2019-12-01 HTTP/1.1" 200 -

So it apparently doesn’t find Grass. I’d like to give some more information about my installation etc., but I’m really sure how to access these informations. I do have miniconda installed and I always do a conda deactivate prior to start GRASS. At least to start the gui this is for some reason necessary (I think for matching the python-version).

If someone has any comment on what I could do or how to proceed, would be awesome:)

Update

I configured my pywps.cfg and modified the line gisbase=/usr/bin/grass78
to
gisbase=/usr/lib/grass78

What I get now in my console is this here:

 "GET /wps?request=DescribeProcess&service=WPS&identifier=sen2_index&version=1.0.0 HTTP/1.1" 200 -
Traceback (most recent call last):
  File "/usr/lib/grass78/etc/python/grass/lib/ctypes_loader.py", line 76, in load
    return ctypes.cdll.LoadLibrary(path)
  File "/usr/lib/python3.6/ctypes/__init__.py", line 426, in LoadLibrary
    return self._dlltype(name)
  File "/usr/lib/python3.6/ctypes/__init__.py", line 348, in __init__
    self._handle = _dlopen(self._name, mode)
OSError: libgrass_datetime.7.8.so: cannot open shared object file: No such file or directory

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/local/lib/python3.6/dist-packages/pywps/app/Process.py", line 236, in _run_process
    self._set_grass(wps_request)
  File "/usr/local/lib/python3.6/dist-packages/pywps/app/Process.py", line 414, in _set_grass
    from grass.pygrass.gis import make_mapset
  File "/usr/lib/grass78/etc/python/grass/pygrass/gis/__init__.py", line 13, in <module>
    import grass.lib.gis as libgis
  File "/usr/lib/grass78/etc/python/grass/lib/gis.py", line 23, in <module>
    _libs["grass_gis.7.8"] = load_library("grass_gis.7.8")
  File "/usr/lib/grass78/etc/python/grass/lib/ctypes_loader.py", line 62, in load_library
    return self.load(path)
  File "/usr/lib/grass78/etc/python/grass/lib/ctypes_loader.py", line 78, in load
    raise ImportError(e)
ImportError: libgrass_datetime.7.8.so: cannot open shared object file: No such file or directory
127.0.0.1 - - [23/Jun/2020 08:24:54] "GET /wps?request=Execute&service=WPS&identifier=sen2_index&version=1.0.0&datainputs=start=2019-07-01;end=2019-12-01 HTTP/1.1" 200 -

grass --config path
export GRASSBIN=grass78 

import os
os.system('grass --config path')
os.system('export GRASSBIN=grass78')

export LD_LIBRARY_PATH=$(grass --config path)/lib