It has been some time since R was updated to version 4.0 and packages on conda support it. Saige is also built with R 4.0 support in conda packages https://anaconda.org/bioconda/r-saige so I don't expect any problems when running build.
Most of those packages are actually available in conda-forge (including cget). It is better to use that channel where possible, than to combine too many channels as to avoid cross-channel dependency conflicts.
It has been some time since R was updated to version 4.0 and packages on conda support it. Saige is also built with R 4.0 support in conda packages https://anaconda.org/bioconda/r-saige so I don't expect any problems when running build.
Most of those packages are actually available in conda-forge (including cget). It is better to use that channel where possible, than to combine too many channels as to avoid cross-channel dependency conflicts.
Conda environment steps were last updated in Oct 2019: https://github.com/weizhouUMICH/SAIGE/issues/118
https://github.com/weizhouUMICH/SAIGE/issues/340