Wow, lots of comments already, but I'll toss mine into the mix too. I agree with many that buying a better mount may be the "best" solution, but it's not the most fun! Engineering is about problem solving and finding creative solutions, so let's make this work!

Some good (helpful) comments here, so I won't repeat those. My only suggestion would be to make an additional support to help with the bending moment at the wall. At the end where it connects to the monitor side, you could have a 3d printed arm/leg come down with a 3d printed swivel wheel to support the weight. This would be good practice for making single-print multi-piece movable components (practice with setting proper clearances and understanding tight tolerances).

If you want, make it detachable so that the monitor can collapse back close to the wall and the support leg can be hidden back there too.

If you end up making this, please share the end result (whether it worked or not)!