FYI we have ~100 different appliances so beyond general Linux stuff, my knowledge tends to be broad and general, rather than deep and specific. While I know bit about Mediawiki, it's been nearly 10 years since I was a regular Mediawiki user/maintainer and I'm certainly no expert. So you likely already know more about your problem than me.
OTOH I'm intimately familiar with TurnKey and have lots of webserver knowledge and a bit of PHP knowledge too. I have also done some maintenance of our Mediawiki appliance. Plus I like to think that I'm a pretty good problem solver. So whilst you've given some details, the clearer and more specific you can be the better. Ideally it'd be good if I can reproduce the issue locally. So here's some questions for you. Hopefully they don't make me sound too stupid! :)
What "security settings" are you are referring to? What specific settings are you changing? What are the steps to reproduce?
Can you reliably reproduce the issue on a clean install (e.g. on a VM)? Or is it only after you've migrated your data?
At which particular point does it break? E.g. straight away, after a webserver restart, after a reboot, etc.
What does "break[ing] it" look like? Does it throw errors somewhere? (E.g. in the web browser, web server logs, etc). If so and you still have the old server, what are they specifically? If possible the explicit error message(s) are useful.
Did you try any specific troubleshooting steps? If so what were they? What were the results?
You note that you've done some reading and it seems that Mediawiki can't do what you want, can you provide links or a more specific summary of that info? It's likely that Mediawiki experts will know more than me - but perhaps if I understand the problem and it's causes better I can either confirm that it's not possible (or more likely "too hard") or maybe we can devise a workaround?
Also something of an aside, you mention that "the migration process" didn't work. I assume that you are referring to using TKLBAM but again it'd be useful to understand exactly what you did and how it didn't work. FWIW you can break the restore up into separate steps and just restore certain components. Often issues occur when migrating data from old servers where some specific settings are incompatible, so doing it stages or only restoring specific components (e.g. your DB and some specific directories).
Anyway, that's secondary at the moment, but I'd love to know more about the issues you encountered as perhaps I can document things things better and/or clarify the notes on the TKLBAM overview doc page?
Could you please give some more specifics on the issue(s)?
FYI we have ~100 different appliances so beyond general Linux stuff, my knowledge tends to be broad and general, rather than deep and specific. While I know bit about Mediawiki, it's been nearly 10 years since I was a regular Mediawiki user/maintainer and I'm certainly no expert. So you likely already know more about your problem than me.
OTOH I'm intimately familiar with TurnKey and have lots of webserver knowledge and a bit of PHP knowledge too. I have also done some maintenance of our Mediawiki appliance. Plus I like to think that I'm a pretty good problem solver. So whilst you've given some details, the clearer and more specific you can be the better. Ideally it'd be good if I can reproduce the issue locally. So here's some questions for you. Hopefully they don't make me sound too stupid! :)
Also something of an aside, you mention that "the migration process" didn't work. I assume that you are referring to using TKLBAM but again it'd be useful to understand exactly what you did and how it didn't work. FWIW you can break the restore up into separate steps and just restore certain components. Often issues occur when migrating data from old servers where some specific settings are incompatible, so doing it stages or only restoring specific components (e.g. your DB and some specific directories).
Anyway, that's secondary at the moment, but I'd love to know more about the issues you encountered as perhaps I can document things things better and/or clarify the notes on the TKLBAM overview doc page?