It has never been easy to create separate users on Linux, certainly not for tasks where you need to switch between contexts.
Docker was amongst the biggest steps forward on this in a long time.
I do not know since when (I am using it for couple of years), but in Arch, it is very simple to have two X sessions (by using "log out" > "switch user") for two different accounts, so switching it's just a Control-Alt-F7 away.
Additionally, one can make the main user part of the group of the development user, so that you can read/write easy in the development user account and it is even easier to share stuff.
While I agree, containerization is awesome, on linux, you can just create a devUser and `sudo devUser theThing`
sudo useradd -m [username] ?
su [username] ?
Or am I understanding your idea about switching context wrong?
I meant for CLI tasks. Just "adduser" and "sudo -u <user> bash".