You can set up multiple inboxes in Gmail so that forwarded emails all appear in their own inbox.
It’s setup so that:
something@mst.edu goes to the mst.edu inboxsomething@cozy.computer goes to the cozy.computer inbox:
This assumes you’ve already set up forwarding from the old email address to the current address and are logged in to the current address.
Go to Settings/Labels and click Create new label. Make two new labels: one for the forwarded emails and one for non-forwarded emails. Mine were called mst.edu (forwarded emails from my old university email address) and cozy.computer (non-forwarded emails).
Go to Settings/Filters and Blocked Addresses and click Create a new filter. Create three new filters and apply the labels we created earlier:
From field and apply the forwarded emails label ex mst.eduTo field and apply the forwarded emails label ex mst.edudeliveredto:something@mst.edu in the Has the words field and apply the forwarded emails label ex mst.edu-something@mst.edu in the To field. The - means NOT. It matches all emails that weren’t sent tosomething@mst.edu. Unfortunately I think it won’t catch a few things, like bcc emails, which might end up in both inboxes. It also doesn’t catch emails from Google Payments or G Suite for some reason.Go to Settings/Inbox, change Inbox type to Multiple inboxes. Place your labels in the Multiple inbox sections area and click Save changes:
is:mst.eduis:cozy.computerNow emails intended for the old email address will appear in the mst.edu inbox and emails intended for the current address will appear in the cozy.computer inbox.