I just finished a bed frame using the corner connectors.
The connectors came with an instruction sheet that was very good. I strongly recommend practicing on some scrap with the exact dimensions of your project. Remember, the expandable anchor can’t be removed once expanded.
I marked every mortise with the desired depth and location as they have to be extremely precise. There just isn’t room for slop.
I went with one solid Domino tenon and one corner connector at each corner. The joints were very solid.