Take a look at the sieve filter capabilities; they are enormous. Here's a simple start for most of your requests:

require "vnd.proton.expire";
# permanently delete after 7 days email from senders.
if address :is "from" ["BestBuy@email.bestbuy.com",
"BestBuyInfo@emailinfo.bestbuy.com"]

{
expire "day" "7";
}

Tons of info and examples at: https://proton.me/support/sieve-advanced-custom-filters

This will keep old newsletters out of my inbox and free up space on your severs. Not to mention save a ton of time in manually cleaning out my old emails and keeping up on new ones.

Would really improve the app for me.

I'd really like to be able to set a self-destruct filter on things like newsletters or special offers, since they're usually outdated after 7 to 30 days.

I can't realistically put everything in the bin for the 30-day delete, as that would mean giving up on the folders I've set up to keep things organised.

Create a custom email filter action that would allow you to self-destruct messages in 7 or XX days based on determined filter criteria. Similar functionality to existing filter action to tag, archive etc., and similar to manually setting a message to self-destruct in 7 days or xx day(s).

This can help maintain control on emails that are only relevant for a short period of time.

There's plenty of mail that would be great to move into a self destruct filter, daily postal mail notification, newsletters, etc.

I'm a brand new user to Proton mail, I've paid for a full year and really want to go 100% and this feature being added would be an amazing addition and it's my first want with-in this application please. I'll be adding more feedback as I continue to switch off of Gmail, I'm so dug in with google this transition will be a hard birth but I'm willing to give it a go, I'm hopeful this small change can be added soon. Thank you

With the ever increasing number of emails, particularly generated by info based sites, I would love to have a way of removing automatically any documents in my inbox that are related to a specific sender / info service that I dont read for X days to be automatically deleted or destroyed.
Selection could be by Label, and an action in the label to Self-Destruct in X days.