Physics are not so bad for interstellar travel.

We just need a an engine that accelerates our space ships with 1g constantly. With that, we would reach something like 80% lightspeed after one year. Exactly in the middle between start and destination, we would turn the ship around and start accelerating towards earth again.

A trip to Alpha Centauri could be done in less than 4 years ship-time. Earth-time would be some years longer.

1g constant acceleration would be quite comfy for humans.

The only thing we need for this plan is the constantly running engine. I propose to bend space-time in front (or behind) the ship, for it to keep falling forwards.