With our 2020 294RL I installed 1200w of solar, Victron Multiplus, Victron MPPT, CerboGX, all associated wiring, fuses and a BMV712. I installed all the gear in the front compartment as I'm still using the original lead acid batteries. When I replace those original batteries I will install lithium batteries and I'm seriously considering moving everything into the compartment behind the basement wall close to the stairs. That said, I think like yours, I have that aluminum frame which runs the entire width of the basement. I would dearly like to remove that framing and replace the walls with sliding panels, possibly plexiglass panels for easy viewing of the gear. There are a few great resources resources you tube to show you the art of the possible. Check out The Dry Campers they seem to do great work, it's a good look at the art of the possible. Best of luck.
2019 GMC 3500HD 6.6L 4x4 SRW