Default Conda Environment?

I have a linux server with conda and python all setup.
It has multiple conda environments and I use it to run a dash server:

(base) ubuntu@myserver:~$ set | grep conda

$ which conda
$ conda env list

conda environments:

base * /home/ubuntu/anaconda3
python_3x_nix /home/ubuntu/anaconda3/envs/python_3x_nix
python_cleaner_nix /home/ubuntu/anaconda3/envs/python_cleaner_nix

I also have TLJH installed on this server.
Under /opt/tljh/user/bin/, I made conda and conda-env symbolic links to the proper conda installation:

conda → /home/ubuntu/anaconda3/bin/conda
conda-env → /home/ubuntu/anaconda3/bin/conda-env

So now when I run ‘conda env list’ from a terminal via the browser, it shows the expected environments:

jupyter-me@myserver@ip-xyz:~$ conda env list

conda environments:

base * /home/ubuntu/anaconda3
python_3x_nix /home/ubuntu/anaconda3/envs/python_3x_nix
python_cleaner_nix /home/ubuntu/anaconda3/envs/python_cleaner_nix

My question is: how can I make one of these the default environment for all users?

So when user john.doe logs in, he will be in the python_3x_nix environment (for example) by default?

And are there are tweaks I need to make so that TLJH users will be in the “main” conda/python environment, rather than the one packaged with the installation?