It works nice minutes earlier, while now whenever click 'Launch Now',
I just get stuck on URL https://firstname.lastname@example.org/lab? with a blank page,
no matter how many times I refresh it.
I have restarted it, now seems to be working ok.
It was quite slow to start, I commented out some things in your .bashrc file. You can try to re-enable them if you like.
Although it’s great you use it in such an advanced way, keep in mind the Lab is meant to be a lightweight, small system. If you want to do such extensive customization of the environment, you should consider using your own system, and using the Lab just to download/extract the data of interest.