IMAP on O365 now requires “Modern Auth”, which requires OAuth to authenticate access to mailboxes. Anything that connects via IMAP will need to be approved by the admins at this point (Including Thunderbird). Without the cooperation of your organization’s IT team, you are not going to get far.

Planka looks very promising too

If you use gitea, it’s just a few steps to enable it to be an OAuth2 provider. See Oauth2 Provider Docs

Not only do they not federate, they also seem to suggest they are not making the self hosting option as easy as it could be because they would prefer one instance that everyone connects with.

It seems pretty solid otherwise, and the self hosted option can work if you are willing to spar with it, but that position makes it super easy for one organization to buy or somehow influence all the primary devs and turn the project closed in no time at all.

Personally, I will use both: On servers with fixed network connections I will tend to use ifupdown; but on my linux laptops I’ll use networkmanager or networkd which tend to have nice UI’s for joining various forms of wifi networks. On my laptops for some VPN’s i"ll use the ifupdown configuration, which lets me setup all sorts of exotic configurations (bridges, vlans, vxlan, vpns, namespaces, etc.) The linux command line tooling has a litany of functions to check/test/diagnose/tweak networking settings, and they work across all the distros, AND they can reveal the full details of the network, as the kernel sees it. NetworkManager, networkd, connmann, etc, often omit details in the name of simplifying for the most common scenarios.