Recently dropped and broke my apple watch, which I use a lot for workouts and work health plan incentives.

Bought an SE3 online and didn't realize I needed iOS26 to link the SE3.

I upgraded and it's been OK, but phone seems a little slower (iPhone 12).

How hard is it to downgrade manually? I don't seen an option on the phone itself to make that work. What I'm seeing online is I need to DL the IPSW file (where can I find one I can trust?) and then manually do it through iTunes with some combination of button pressing/resetting the phone.

I think it requires iTunes.

You need the .ipsw file and can use itunes. Hold shift and click restore and it should let you pick the .ipsw file you downloaded.

Rub is... the iOS versions still needs to be one signed by apple or it won't let you restore.

Also you won't be able to downgrade the WatchOS, and may run into issues with 2 major software versions if they are too far apart.