Best on-stage guitar speaker solution?

My current band has too many members, so I often stand fairly near my cab. This can make it hard to hear my own amp.

Cab is always a 2x12, usually a Marshall, but mounted vertically to save space and also because (ignoring the counter-intuitive science) it means the upper speaker is nearer my ears.

I tried, and immediately gave up on, a proper vertical/angled cab which made close to zero difference.

Obviously (ha! not obviously at all!) 2x12 sitting horizontally has better vertical spread, but I doubt that would make enough difference if you’re standing 1.5m from your amp.

Wondering if using an open backed back might make a difference?

In-ear, and other rock-star solutions not really an option. Any ideas would be great!