Hi @schuemie, Thanks for your presentation. I wanted to suggest using conda as a package manager. It is much smaller than docker and you can specify the R version. It is also very stable. This should address some of the concerns you mentions about docker and renv.
After downloading miniconda or anaconda, code would be
conda create -n renv
conda activate renv
conda install -c conda-forge r-base=4.1.3
specific packages can be installed with the r- prefix
Happy to create any specific sample env files to fit your use case