Please note that I found a 7 parameter similarity transformation (3 translations, 3 rotations, 1 scalefactor) definition for GDA94 to GDA2020 or WGS84 which is equivalent in
https://www.icsm.gov.au/sites/default/files/GDA2020TechnicalManualV1.1.1.pdf. These parameters are:
[𝒕𝒙, 𝒕𝒚, 𝒕𝒛, 𝒔𝒄, 𝒓𝒙, 𝒓𝒚, 𝒓𝒛] = [0.06155, -0.01087, -0.04019, -0.009994, -0.0394924, -0.0327221, -0.0328979]
Because of sign rotation convention the TOWGS84 entry should be set to
[0.06155, -0.01087, -0.04019, 0.0394924, 0.0327221, 0.0328979, -0.009994] in your prj file....
Attached is GDA94.prj that can be used in Metashape to do transformation from GDA94 to WGS84 or GDA2020
Following are coordinates (long,lat,h) of Point Alice Springs (ALIC) first in GDA94 with correct TOWGS84 parameters and then in WGS84:
chunk.crs
Out[7]: 2020-04-08 05:03:25 <CoordinateSystem 'GDA94 (EPSG::4283)'>
chunk.crs.towgs84
Out[8]: 2020-04-08 05:03:40 [0.06155, -0.01087, -0.04019, 0.0394924, 0.0327221, 0.0328979, -0.009994]
marker.label
Out[9]: 2020-04-08 05:03:56 'ALIC'
marker.reference.location
Out[10]: 2020-04-08 05:04:15 Vector([133.88551330000004, -23.670123899999997, 603.3465999991015]) i.e. (long, lat, h)
chunk.crs
Out[11]: 2020-04-08 05:04:40 <CoordinateSystem 'WGS 84 (EPSG::4326)'>
marker.reference.location
Out[12]: 2020-04-08 05:04:50 Vector([133.88552161855534, -23.670110143743194, 603.2488552965314]) i.e. (long, lat, h)
This corresponds to example transformation given in above cited Technical Manual (3.1.1)...