I would like to have another printer still next to my ROBO R1 Plus, pretty good printer. I would like to make my own, build a kit, or use a preassembled printer. Any thoughts ?

Look into deltas, you can find many different delta kits and they are very interesting kits, I built a GeeeTech Rostock Mini which has great customer run Google forum. Just my opinion.

I am thinking about buying another Robo to add to the one I have now.

The orbeloprinting prusa steel or p3 steel toolson edition. It’s a prusa i3 like the Joseph prusa, hictop, geetech, wanahoo, gmax, etc with an all steel frame and it prints beautifully. For Delta’s the richrap 3DR is a fun build, kossel or the geetech kits.

Also: Best 3D Printer Guide 2023 | Hubs 3d hubs has a budget section in the printer guide. The guide is compiled using reviews from actual printer owners on 3d hubs.

Qidi is a knock off, but I love mine NO PROBLEMS EVER!! few hundred hours++++ I love my geeetech deltas but they are a pain to assemble and operate, NEVER get a ctc lol though I think they may be the real manufacturer of Qidi …no idea lol… but My qidi was ready to print right out the box, all metal and very well built metal gears and EXTRA heavy duty cables!!! love it for 650 or less…

+1 on qidi and on avoiding CTC. If you want to do the work and take the risk you can also get flash forge creator pros for $450-$550 . They are returns so there is a percentage risk that something will be broken on the unit. (My last one has two loose screws)