I think this is semantic. At our company we use kamban, but each step is pretty literally a step (we move back and forth between being too detailed and too focused). For us, our main definition of a "step" is a handoff. When work moves from one person to another, make a new step. Examples include to do, in progress, PR, pending qa, pending push to staging, etc. Some steps are optional, some required. Basically I think people should use Kanban tailored to their team workflow.

But if you are in, "in progress" for example, how does anyone knows it is done if you don't have the two columns? More so in your case where you do handovers.

Not GP, but the traditional kanban way is for the doer to move it to the next column. The reviewer can then move it back if they’re not satisfied.

Kanban has branched into so many different directions from the original, since people feel inspired to create their own boards. The double column approach may have its own advantages. What bothers me is when tools layer on more functionality that interfere with the basic act of moving items between columns. The last iteration of Microsoft’s kanban tool wanted you to set status by right clicking and coloring. By clicking done the task would vanish from the board. In their conception of kanban the columns were only for categorization and not for a process.

When it is done, you hand it over to the next column, right?