it's also much too trusting of the senders From field. I get emails all the time that look like they come from Apple or a bank, etc. I have to tap the name before it shows the actual from address.

Yeah that too! I've only had an iPhone for a few years but as soon as I used Mail I immediately understood why my parents got phished. Mail hid all signals people would normally use. Their spam detection is bad too. In my first week I got a PayPal used to buy bitcoin scam and neither Gmail nor Thunderbird showed it (both flagged as spam). Both also just showed it was an empty email with only a PDF attachment whereas Mail showed what looked like a normal email, including an address that looked like PayPal's.

I also notice it doesn't handle relayed emails well. I have a bunch of dummy emails and Mail doesn't show me the relayed name, which really hinders my ability to track and combat spam

I agree, I often find what I am searching for quicker by using the Gmail app instead.