Turning off security

I appreciate the reason NC and its apps seem to have very strict controls on file modification and barf if (seemingly any) changes are made to any file or if permissions are “wrong”.
This is all very sensible and impressive in a public and high profile environment where you might be paranoid about someone “stealing” “your” data or messing with your site.
(although it doesn’t seem to be a problem for the vast majority of sites using php without any lockdown aside from basic access controls - thinking of major and popular CMSs which have very simple hooks for people wanting to extend them)
The trouble is this is a frigging nightmare in a private low profile environment where you might want to tweak various apps and the core, hack your own without all of the faff of having to build/make/compile a very simple php & js fileset which doesn’t need it.

Is there ANY way to turn of all of the security checking. For heavens sake NC even complains if you put a file it doesn’t know in the root folder - perhaps a standalone html/php info page. This is sometimes just silly.

It really does seem a little restrictive and OTT.

I don’t have those security restrictions with a git checkout. How to setup a development environment is documented at nextcloud/server on GitHub.

Ah, that’s interesting. Thanks I’ll try that.
I’m just used to being able to hack around ad lib on a test/staging/backup install on a macbook with MAMP and then simply copy stuff across to live when it is done.

Hmmm:

Error
Mac OS X is not supported and Nextcloud will not work properly
 on this platform.  Use it at your own risk! 
For the best results, please consider using a GNU/Linux server instead.

Hrumph. Is this a genuine warning or will it actually work ok. Anyone else out there using a mac for development? Anything particular I should know? What exactly will “not work properly”?