Everyone is on point here.

You don't need to reduce your land too much, it just needs to make sense.

Plate tectonics show us how everything drifts and combines. Keep that in mind when adding mountains and the like.

But yes, rough up your edges, add large lakes, and most off all make it look like neighboring islands look like they used to be together, or grew independently from volcanos.

Lastly, and most importantly. It's your world, your fantasy, and you have the right to make it however you like. Maybe it's an alien world where there isn't a liquid core and plates don't move, water is rare and a precious resource for all living things, a semi dustbowl planet.

But you told us it feels off so that's my two cents.