First Apple Watch! I’ve only had it for one day and honestly the size isn’t too bad. Debating if I should exchange for a 41mm. I’ve had this 38mm seiko as my daily for the past year and sizing is somewhat similar because of the lugs.
Keep it, the size is great. If you look at the third picture, the dial itself is actually a bit smaller than your Seiko. So 41 mm may look too small for you since you’re used to your Seiko.
Looks good I say keep it. My recommendation would be, if there is a store near you take a few minutes and sit there with a 41 on, get up walk around the store and look at it and scroll through a few screens.
I am sure you’ll appreciate the extra real estate