How to activate conda and a specific conda env for each shell and subshell in a singularity container

Question

I have been trying this for a few days and no success. I am building a Singularity container (version 4.0.2-jammy), and I want to use conda within it. I am able to install conda, create the environment, and apparently activate conda, but not the environment, as I run singularity shell. Here is the singularity definition:

Bootstrap: docker
From: rocker/tidyverse:4.3.2
Stage: spython-base

%files
. .
%labels
org.opencontainers.image.licenses='GPL-2.0-or-later' 
org.opencontainers.image.source='https://github.com/rocker-org/rocker-versioned2' 
%post


CTAN_REPO=https://mirror.ctan.org/systems/texlive/tlnet
PATH=$PATH:/usr/local/texlive/bin/linux

# Install Miniconda
wget https://repo.anaconda.com/miniconda/Miniconda3-latest-Linux-x86_64.sh -O /tmp/miniconda.sh && \
bash /tmp/miniconda.sh -b -p /opt/miniconda && \
export PATH="/opt/miniconda/bin:$PATH" && \
conda update -y conda && \
conda env create -f ./environment.yml && 

echo ". /opt/miniconda/etc/profile.d/conda.sh" >> /etc/bash.bashrc
echo "conda activate $(head -n 1 environment.yml | cut -f 2 -d ' ')" >> /etc/bash.bashrc

%environment
export SINGULARITY_SHELL=/bin/bash
export CTAN_REPO=https://mirror.ctan.org/systems/texlive/tlnet
export PATH=$PATH:/usr/local/texlive/bin/linux:/opt/miniconda/bin
export PATH="/opt/miniconda/bin:$PATH"


%runscript
exec /bin/bash "$@"

%startscript
exec /bin/bash "$@"

However, as I execute a bash script from the container, I obtain the following error:

CondaError: Run 'conda init' before 'conda activate'

However, if I just run singularity shell myimage.simg I can successfully activate the environment.

I tried to activate the environment in multiple ways, using the %environemnt, %runscript%, and %startscript sections. As you can see, I also modified the .bashrc and forced conda to use bash with the configuration. I also tried to add . /opt/conda/etc/profile.d/conda.sh and conda activate myenv in the mentioned sections. However, no success. Any help is appreciated. I would like to ensure that my environment is active in all processes and subprocesses executed by the container.