I have an Ocean Optics USB2000+. It is by far the best of all the spectrometers I have used. Much better than the B&W Tek ones I have used, but they don't come cheap. Even used ones come at a higher price than most are willing to spend here. You will also want their software to run it on, so......more money.
I agree the usb2000 or hr2000. Look on eBay. You can pick it up for 1k. Ocean optics will want 5k.
Mine does 200nm -1120nm. No issue. I’ve measured from 266-1100. No problem. It’s about 1nm width. In the visuali have split 0.5nm with a blob peak.