A new feature in QGIS 3.40 is the Cloud layer browser for addition of easier data in Azure or AWS S3 etc. Previously you had to add an environment variable with the connection details, now those details are saved into the layer definition in the project.
I’m currently running qgis server v3.38.3 with LMWC v3.7.8,
Does Lizmap 3.8 /QGIS server 3.40+ allow display of ‘cloud’ raster layers?