Scheduling is a wonderful thing - but at this time the inbuilt conferencing option is limited (e.g. 9 participants). Why not support different meeting provider through their apis? We currently use wildix and they support an api to create and delete meetings.

Integration into an ecosystem is the main driver for replacements of solutions like ms365 as they tightly integrate different functionality stacks. To replace such a stack you need a) email with smartermail b) uc with some uc solution c) file storage d) only editing through some wopi interface.