Try momondo.com. You can add # of luggage (checked in & cabin) and play with some other parameters. They won't, or very rarely will, show train connections. They sometimes show bus connections, though.

For train travel I find trainline.com quite good. It gives you an overview over what's available an with which carriers. They are UK focused but offer tickets throughout Europe.

The Man in Seat 61 is (https://www.seat61.com/) is an invaluable resource to inform yourself about train travel. Mostly focused on Europe but covering the world.

Hope this helps.

Edited to add : I use Momondo as an information resource about available carriers and pricing for specific routes. I would never book via an OTA, but strcitly with the airline executing the flight. No matter if it's a few franks more.

If there's any problem with your flight you're up shit creek if you have to deal via a third party.