Moving 30 office users from Windows to Linux. Where should I start?

Ubuntu LTS is a sensible starting point, especially if you're the one who'll be supporting it. Familiarity will help when something breaks. Linux Mint is another desktop option worth testing if you want a different interface.

Don't switch all 30 people at once. Pick a few users with different jobs and test their actual workflows, including printers, VPN access, authentication, and any business-specific software. Make sure you have a way back if a critical task doesn't work.

Start with the reason for the move, not the distro. If the goal is saving money, compare the licensing savings against setup time, support, training, and disruption. Moving only servers to Linux might be worth examining too, rather than replacing every desktop.

For mostly browser-based work, Chromebooks or Chromeboxes are another option to price out. On the other hand, reusing existing PCs could make Linux desktops more attractive.

FreeIPA and Ansible can be useful parts of the setup, but they solve different problems. Think through how users will authenticate and how you'll configure and update machines, especially laptops that may not always be reachable on the company network. Test those cases before assuming a central management setup will cover them.

Document collaboration needs its own evaluation. Nextcloud is one option, and browser-based services like Microsoft 365 or Google Workspace are others. Linux on the desktop doesn't automatically mean giving up Microsoft 365.

Ask the people doing the work to test their real documents, particularly spreadsheets used by accounting. A shared file opening successfully isn't the same as every necessary editing workflow working well.

Be realistic about the support burden. This can be done, but replacing an entire desktop environment is more than installing an OS. Budget time for preparation, user training, troubleshooting, and ongoing maintenance, especially if you're the only person managing it.