Hi triplehjr,
Welcome to the Apple Community, where some of us do our best to help each other :)
Wondering which operating system is installed on your iPhone SE.
Apple support have articles online (click the blue links below) that may help:
(You can choose your operating system at the top for the most accurate info.)
View an email in Mail on iPhone:
You might want to scroll to "Show the whole e-mail"
and /. or
Show To and Cc labels in your Inbox
where you can edit the settings
https://support.apple.com/en-au/guide/iphone/iph3caef48c/ios
Also:
Wondering if you use iCloud on your iPhone?
Apple support have this article online:
View long email headers in Mail on iCloud.com
hthttps://support.apple.com/en-au/guide/iphone/iph3caefa61/ios
__________________________________________________________
Or
Would filtering (or "flagged on arrival") e-mails be any help in sorting out your e-mails from your separate addresses:
Filter emails
You can use filters to temporarily show only certain messages
—the ones that meet all the criteria you select in the filter list.
Emails can also be flagged: see
"Flag e-mails from your listed VIP's:
so their emails appear with a VIP flag, and in the VIP mailbox.
(You may wish to have all e-mails to one of your addresses to be flagged on arrival ?)
Flag and filter emails on iPhone:
https://support.apple.com/en-au/guide/iphone/iph3caefa61/ios
____________________________________________________________
Also
Organize email in Mail on iPhone:
https://support.apple.com/en-au/guide/iphone/iph376ef8aa3/ios
Search for email in Mail on iPhone
(You may wish to search for all e-mails to one of your addresses)
https://support.apple.com/en-au/guide/iphone/iphb2eab8035/ios
Hope there is something useful for you here :)