I have done IT for small businesses. Every small shop I worked for had to use many different and incompatible assortment of software tools to set up the IT for the business: Windows system for a proprietary billing software, OpenBSD system for routing, proprietary intercom tech. I envied my friends who worked for proper software companies. They could build everything for Linux, dockerize everything and done!

Is there anything like Kali-Linux but for business tech? I would love it if I can find one Linux bistro for business tech that rules them all!

I'm lacking details from your wish of course, but if you need to run several, disparate different software....Could not one of the common linux distros like Ubuntu, Redhat/Fedora, SUSE, etc. suffice, and of course have a powerful enough machine to run virtual machines or maybe WINE? Obviously this depends on whether you were asking for client side or server side...And if on the client side, things - as you know very well - can get very tricky because you then have to deal with training and general acceptance.

When i used to have my IT side hustle company, whenever i supported software for small businesses, i often found that nuding them to web equivalent software made things alot easier. For example, some users get comfy with software faster when its within context of a web browser...Of course, this is different for every user/org and with different software, it depends. But it lessens your support away from conventuional desktop supporot. However, if the web softeware is managed hosted then its much easier, but if you have to manage the hosting, then you would need web management sort of skills. for me that was my forte, so it was easy for me.

As to your wish to find a linux distro for business tech, there are platforms like Odoo (see wikipedia: https://en.wikipedia.org/wiki/Odoo)...but they're not lightweight, and back to my earlier point, you'd have to build up your skills administrering web apps, server, etc. I'm sure there are plenty of other options beyond Odoo. Try a couple of searches against odoo; the old google hack of "odoo vs..."

Good luck!

EDIT: Sorry, i meant to direct my comments aboive to @importgravity :-)

Most people see this as some sort of tax to provide better support, which should not be the case. We need better tools at reasonable and transparent pricing. Hope we succeed in that mission.

What tool are you using?

from the sounds of "single biggest expense", I'd guess Intercom