I can't really fully understand what "Microsoft 365" stands for. Microsoft years in day? Microsoft all year? hard to understand. Sounds like some kind of new super-term for their Office products. In that case, LibreOffice works absolutely fine inside my company. Element works alright for secure e2ee messaging. For storage and document collaboration we are using a self-hosted Nextcloud cluster. All of these solutions are free and have no upfront fee, but they have some maintenance costs of course, yet I think they are magnitudes lower that M$ could scam us for. The AI tooling you can definitely integrate in the workflow yourself if you need them (we don't). As non-us company inside security field, we have little trust towards microsoft to store the sensitive data on their cloud services, and generally the amount of measures taken against corporate espionage is higher – communications are taken through verified and trusted e2ee mediums, and it's common to host enterprise infrastructure on-premises – it's totally realistic to have your company data and communications never leave your virtual private network, and it's a good practice to do so in my opinion.