Hi Ondrej T
Thanks for visiting Microsoft Community. It's great to hear that you are helping the charity refurbish their equipment, thank you so much for all you do, Best Respect!
I wish I could handle your problem, however, it is more suitable for publishing on Microsoft Learn, more users post these issues there, you can click on "Ask a question", there are experts who can provide more professional solutions in that place. Here is a link to the forum where you can raise specific scenarios and share your idea to help solve the problem.Sincerely hope that your question will be dealt with appropriately after contact the correct department. Thank you for your understanding!
Best Regards
Arthur Sheng | Microsoft Community Support Specialist