I would say hold out for what you really want, the wait is just the way of the world these days, I ordered my RLD topper in Jan. 2021 and got in Late August/Early September of 2021, so they are spot on for the 8 month wait. There really is no comparison to any other topper, as the RSI is modular and bolts together and the Alu-Cab is aluminum and lighter but it's roof holding specs are much lower than the RLD. I can't speak to the side windows as I went with the solid doors and for your purposes I wouldn't recommend the solid doors or the solid windows, in that you can't open the side doors from the inside. That would be a PIA if you wanted to shut them because of rain/snow/etc. I can say IMO that the quality is worth the money. If I could do it all over again, I would not get the load bars and platform nor would I get the table mount.
The reason I would not get the load bars and platform again, is that it sits too high not only compared to my Rhino Rack backbone platform over the cab, but the RLD platform is designed strangely in that you can't use standard awning mounts on the sides as there is nothing to attach to, so I have to make up brackets that attach over the platform and not directly to the platform. Because the design of the canopy/topper has three raised sections on the roof and the platform attaches to the load bars and not directly to the roof, it's raised 3 inches, but you can't use the space underneath it. Yes, this height does allow the positive pressure vent to open fully. I've ordered a Rhino Rack platform and plan to remove the RLD load bars and platform and mount the Rhino rack platform directly to the raised sections of the roof to the canopy/topper.
The reason I don't suggest the interior table mount is that it hangs down too low and the table is not flush with the roof, this causes two issues IMO, it robs head room, in that there is about 2 inches of space between the table and the roof. The supplied (lifetime knockoff) table shakes in the mount. I would suggest saving your money and mounting a table directly to the inside of the roof.
I do have two of the cupboards, but haven't installed them yet, but they are one piece and appear very stout.
I would also suggest buying it from a dealer and having them install it. The install is not difficult at all, but you do need at least 4 people to lift it and the pallet/wooden box it's shipped in is a big PIA to dispose of.