The best way to allow multiple submissions while amortizing the review work is to make reviews (and rebuttals) public, and overlay them on submissions made public on some preprint server.

This establishes priority (if credit is a concern), can be made blind / double-blind if so desired, and also makes public the reviews (which are as much a public service as writing research papers). Which editorial boards “accept” the paper for publication is then simply a matter of collecting endorsement tags on the submission.