I switched from GMail to Fastmail about a year ago, but ever since my Inbox is just filled with lots of spam. I tried writing email filters, and have about 50 now, but it is just not cutting it.
And also those promotional mails that I don't want to mark as "spam" but still shouldn't end up in my Inbox ... they drive me nuts.
Since I started using Fastmail, my main means of communication is shifting away from e-mail, which is sad.
For the promotional emails, there are some general rules you can set up to catch a lot of it, such as https://pietrorea.com/2021/10/22/filter-emails-by-the-list-u.... However, the best way to manage them is to actually just unsubscribe to them as you receive them. If unsubscribe is ignored, then blacklist the sender.
For general spam, there's a setting under "privacy and security" to make the filtering more or less aggressive. My setting is on "standard" and I haven't had any problems, but you could try adjusting that.
But I still think migrating away from GMail should be less painful.
Some stuff like promotions or social messages deserve their own folder. Google did this right.
They have millions of users and they use aggregated data from all of them to manage the automatic categories.
(By the way, in GMail you can move emails to "promotional" and "social" folders, and then GMail automatically does that for you for future emails; this is quite handy, but after migrating to Fastmail this is leaving me with quite a mess in my Inbox, since Fastmail doesn't have this option).
It's not quite as elegant, but you can create a rule from an existing email in the mail options. It will try to guess at the best set of filters to match that type of email (and obviously you can refine that manually if needed), so you can send those types of mails to a Marketing folder.
For better or worse if you want to reliably control who you receive email from you need to control who knows your email addresses and have the ability to disable/filter them.
If the email gets sold, just tell the fastmail UI that everything sent to that address is spam. It hasn't failed yet, and i've been using fastmail since it was $5/year. It's $15/yr now and they recently doubled my storage from 500mb to 1000mb!
Matches NOT fromin:contacts -> Move to Screener
I'll check the Screener less frequently, and whenever I feel like it I'll take a message from it and use Actions -> Add rule from message.. and send messages from that sender to a Newsletter folder.
I still get lots of crap in the Screener, but then again I don't really use e-mail to communicate with humans, so in a sense all e-mail is automated nonsense from systems where I have some kind of user account.
Then, I send everything with a score of 5 or more to spam.
I don't delete any spam.
And I mark it all as read.
That cuts down on spam drastically in my inbox while still retaining it all in the spam folder should any legit email end up there.
That's what I've been doing and my inbox is pretty much empty from useless stuff.