Thanks for the replies Folks.
My goal in all things is always simplicity...
Using that other (inferior IMO) OS as my example - my aim as expressed here was attainable in it quite easily in about a minute via either=>
1 - Installing TB as a 2nd instance in a different directory, or;
2 - Using a portable release of it in a separate directory.
A possible TB compatible client and solution could possibly be found here:
https://binaryoutcast.com/projects/interlink/download/#linux
At one point I did get it but stopped short of actually trying it because of my tolerances for flakiness having already been exceeded by the flaky non-support associated with the Palemoon browser - thus it was deleted so as not to tempt me any further.
I could easily make a minimal VM to accomplish the goal of separated instances - and I do still have a VM of XP on hand that almost never gets any use.
IMO there should be a simple, easy way to have 2 separated instances of TB under Linux which could be opened at the same times MINUS the need for any exotic solutions.
Sure, no OS can ever be 100% perfect such that ALL its users are 100% perfectly happy at ALL times - but in that area, here is my silly example:
Before switching totally to being a full time Linux user, I was a great appreciator of portable apps.
Being able to do this or that with zero (or very little) system overhead was wonderful - as was the ease with which an entire app along with its data was transportable.
AFAIK, the closest that Linux comes to this is APPIMAGES - but=>
Using TB as my example, the same architectural flaws apply wherein it MUST use the same profile(s) as the installed TB, so...
Why bother ?!?
Lastly, this brings to mind that decades ago it was my pleasure to be the very 1st tech support guy for a large organization starting out with the original IBM PCs which mostly had DOS v2.11 at the time.
Having to memorize so many commands with their associated & mandatory syntax was a thrill for my younger self as well as enjoying the work itself.
Today's world is NOT the same as it was ~30 years ago.
Granted (IMO) PCs really haven't evolved THAT much as compared with even a high-end, unlocked Android smartphone.
I have zero interest in Docker or any of its spinoffs for the same exact reason that I refuse to learn any 'language' for coding:
Too much effort in memorizing esoteric stuff aimed at attaining a very narrow goal.
Should someone have a really cool sort of app that SIMPLY creates something like an OS (image ??) within the running OS which makes it utterly simple to have additional, isolated instances of system-installed apps, I'll be curious to check that out - as long as it isn't going to have me riding the learning curve any longer than the time it takes me to make my breakfast (as in...not very long a'tall !!).
Thanks Again.