I have a BCN3D Technologies Sigma 16, which is a couple versions behind the current crop of IDEX machines. Independent Dual Extruder printers are great for your reference to water soluble supports. I've been using mine with ABS on one side and HIPS on the other, but not dissolving it, as the disparate materials separate quite easily and leave clean surfaces.

Software today recognizes the cost of the support material and uses the stock material (PLA, ABS, etc.) up to the interface and then puts a few layers of support in place. Big money savings as a result.

The Sigma line supports mirroring and duplication, which uses both heads simultaneously to double the output if you don't require support.

One of the reviews I watched regarding the model line criticizes the bed heating and I recognize that it's somewhat uneven, but it hasn't caused me much trouble. The glass bed sits a millimeter above the heater and the air doesn't transfer heat as well as direct contact, which means it takes longer to heat up and also has a cold perimeter. I use Elmer's glue stick (purple) to prevent problems in that respect.

It's not an enclosed printer, but I slapped a sheet of acrylic over the front opening and get great ABS results. I think nylon would be challenging, but I've printed NinjaFlex with minimal problems and a good bit of stringing.

The new batch of printers they produce have all the updates including some rather quiet stepper drivers as well as "intelligent" fan control. I upgraded mine to the Bondtech extruders (now standard) and new stepper drivers and it's a night-and-day difference in quiet and performance.

One aspect I dislike greatly is that one cannot replace only a nozzle. This is just wrong, in my opinion. One must purchase an entire hot end assembly; heater, nozzle, heat break, heat sink if one wishes to change nozzle size. Unwarranted expense which means for me that I don't have the desire to implement such flexibility.

I used a Thingiverse mod and placed my extruders and spools outside on the back of the enclosure. It makes for easier loading and unloading but that's an option for later.

I paid just about US$2500 for my printer and I'm not sure if you will find something new in your price range. IDEX is definitely the way to go, if you can find one you can afford.