If you had $1500 to spend

I’d buy a prusa core.

I'd buy a printer. If you're looking for something easy, an assembled Prusa Core One. If you want something more expandable/project-like then probably a Voron.
Edit: a letter
- So I've never considered a Voron before. I'm looking at it now and I went through the configurator. I have a spreadsheet of parts and links to the supplier. Do you just order all these parts from the supplier and then I put it together myself? Do I have to solder? I suck at it.
  I've considered a Prusa. Definitely one of the best (if not the best on the market). I was sort of hoping for a larger print bed.
  
  There are a ton of great printers under $1000 these days. If I needed a larger bed I'd get a Qidi Max 3. I got an Anycubic s1 with an ams that dries for $600.
  
  Or you buy a kit from a reputable brand
  
  You have four paths to get parts for a Voron:
  self source all the parts individually
  get kits for the things you want and self source what you want to be picky on. For example, here's a motion kit
  configure a kit from someone like West3D
  buy a BOM in a box. There are a couple of brands that do this
  I personally went the West3D route. It seems like the LDO and formbot BOM-in-a-box options are popular. If you live near a microcenter they offer smaller kits if you want to mix and match or use a brick and mortar. Self sourcing tends to be expensive due to our collective tendancy to buy higher quality than necessary parts and shipping.
  Yes, you will be building the thing from a ton of parts. Yes, it will take you a while. If you're comfortable building things there's nothing particular hard about it. You absolutely will not need to solder. Most kits come with premade wiring harness and there's plenty of complete wiring options available even if you buy components. Depending on your goals, you might need to customize your wiring some. This means crimping, which isn't hard per say but you'll probably need to buy a crimper or two and dial in the right amount of squish for your terminal and wire gauge combination. Too much force and you'll wind up severing the wires. Too little and the terminal will come off the wire. Again, not hard but you'll probably need to do it a few times before you develop a feel and get consistent.
- I wish the Prusa Core One had a larger print bed. I'm looking over the specs on their website and it is a nice setup.

I mean I would need to know what the problems were with my printer. When I had an Ender3 v1 and I was debating upgrade or switching. I went with switching since the machine had fundamental issues which couldn’t be fixed or the solution was not guaranteed to fix it.

The new printer, hands down (unless your goal is to push the viper beyond its limits). That kind of budget puts you far beyond entry level machines, and usually comes with marked improvements in quality, reliability, and speed. For example, with 1.5k you could probably swing one of the big Vorons 2.4 kits on sale (+printed parts), a Trident kit at retail (also with printed parts), or go the out of the box route and comfortably pick up the Core One (or go Bambu if that's your jam).
For context, I can run prints on my 2.4 what would take something in the neighborhood of 4 times as long on my old ender 3.
- I'm looking at the Vorons now. I like that I can build it to spec.
- For context, I can run prints on my 2.4 what would take something in the neighborhood of 4 times as long on my old ender 3.
  I would put the difference even higher between my 2.4 and my old i3 clone, but I'm also running a 0.6mm nozzle and print with 0.9mm extrusion width / 2 walls and 0.3mm layer heights. My limiting factor is volumetric flow, which I've found to vary between materials (ASA = way easier to print fast than PETG).
  
  How fast are you printing? I'm very close to finally pulling the trigger on a 2.4, and would love a bump in speed. my current printer (Anycubic bedslinger with klipper) is printing PLA/ASA at 200mm/s with 6000mm/s2 accelerations and 300mm/s travel while retaining pretty good quality.
  My biggest annoyances with my current printer is that despite the probed bedmesh (inductive probe) it doesn't compensate properly on the first layer across the entire bed. There's a 0.1mm difference between highest and lowest probed points, i would think this could easily be compensated for since it's decently flat. But it always ends up with bad sections where it's clearly not compensating correctly while others are perfect. I also always need to tweak Z-offset between powerdowns, which is a bit annoying since i usually need to restart the first print of the day at least once. How consistent and close to "set and forget" is your voron?
  
  Do you have any suggestions for upgrading the base kit? There are so many options.

That'll get me a new Prusa with some to spare for filament. Unless there's a clear and specific use-case on my plate that a Core One or mk4 can't do, I'd get a new printer.

I'm sorry, but it's shameful so many people are telling you to spend $1,200 on a printer because of the brand when you can get an identical or even superior feature set for half that or less. They have fallen so far behind and the loyalists just cannot admit it.
- True, I knew that my Voron would work out to be more expensive than the leading competitor, but I also highly value the open source ethos and saw it as an opportunity to put my money where my mouth is. No regrets and I'm happy to champion it, but I do try to present other options on the field.
  My broke college student days aren't that far behind me and I can appreciate the hell out of a value option. I'm very curious what route you have in mind.
  
  I wasn't really speaking on a voron as it's far superior to another recommendation people are making, and honestly ALWAYS make when people are considering a purchase.

I would not.

For that price I can get 3-4 Ender-3s and the same number of Raspberry Pi and make my own smart printers .