Nextcloud, Qbittorrent, Truenas and loads of other svcs take optional email credentials for sending alerts and other features (eg. password recovery for nextcloud).
What email providers do people usually use to make this process simple to set up? For example, Microsoft doesn’t allow basic auth anymore so it’s supposedly not possible to use via most of these setups, and some other services seem like they have a low inbox size (does this matter?)
Self hosted ntfy and mailrise. Mailrise is a wrapper for apprise that let’s you send emails to it and in turn converts the email to the desired push alert.
For password resets or account creation welcome emails I’d use a SMTP service. I use SMTP2GO for those. Free plan is something 1000 emails a month. I’ve been using them for a year and think I’ve sent maybe 5 or 10 emails.