Help for a particular use case

Hello friends, I'm having trouble. My department (higher ed) has been using Constant Contact for years and years to run our newsletters. Suddenly the newsletters are not arriving. IT tells me there's nothing they can do because it's the spam filter of the university blocking the emails, and the filter consults with larger spam filters and can't whitelist these IP addresses because Constant Contact is used for spam by OTHER people. My beloved newsletters are collateral damage in the arms race. Constant Contact also can't do anything about this of course because they can't control who puts their IP addresses on spam lists or doesn't. Basically our CC account is useless now. So I'm looking for an alternative way to send out newsletters.
All I need is:

- A drag-and-drop email editor

- The ability to control or direct where the email comes from, or otherwise ensure that it won't get blacklisted... somehow

I don't even need the ability to store contacts because I could create a university mailing list instead and know that that wouldn't be blocked. But I need some way to get the email in the first place so I can send it out, and I no longer get emails from Constant Contact! Does anyone have any ideas? Looking at Constant Contact alternatives is overwhelming because so many of them are like "use AI to bother your customers on their phones immediately when they leave socks in their cart for more than five minutes" and I just need to get information to our students via University email. Any advice or help at all would be appreciated.