If your local Trek dealer can't come up with what you want, they may be pushing what they have in stock. Make sure you get what you want in the correct size.

The 520 had a steel frame, I assume the replacement will have an aluminum frame. Is this the bike you had?
https://99spokes.com/bikes/trek/2021/520-disc

That had a 3X system.

You should also ask them to check with Trek to see if they have any new old stock 520 frames in inventory that they could swap the parts too. Or check with other Trek dealers too. I know a guy that had a cracked Trek frame. Trek gave him a replacement frame, but he had to transfer the parts over, no labor was provided by Trek for that.

Will your racks mount on the new bike?

I have some friends that always have to have the latest thing. So, several years ago, the latest thing sounded like a gravel bike. So, one bought an aluminum frame Checkpoint and liked it. Got one for his wife too. And another friend that hates to be outdone, bought a carbon frame Checkpoint. And then another friend bought a carbon Checkpoint with carbon wheels. All four of these people that I know that have Checkpoints are quite happy with them. But, none of them ride with a loaded bike, so not sure if their opinions are applicable to your situation.

Ask if you can keep the parts from your old Trek, just in case you find a use for them later. For example, you might like having a second set of wheels.

Good luck.