You’re only looking at half of the expense. You still have the ventilation and required make up air to factor into the budget. They are inseparable. And that means that you only have half the money that you think you do for a range.

A standard 30” consumer grade range makes the most sense for those on a limited budget. It also is better for the small kitchen that is usually associated with a small budget. More counter space.

"NXR, Thor,and Kucht - all which seem to be regarded ,imported models"

NXR, Thor and Kucht are "regarded as imported" because the manufacturer, Hyxxion, does make/assemble them in China and then ships them to North America for sale by marketing companies.

"it seems like more of the negative reviews on these ranges are from a
few years ago,and the more recent reviews seem to be mostly positive"

Well, sorta. The Hyxxion-made stoves are pretty much knock-offs of the relatively simple, sealed-burner Wolf & DCS designs from the 1980s, but they are shipped a very long way. That makes them more subject to shipping damage. Also, some folks do receive lemons. Post-sale service and support is still hit or miss, can be slow and otherwise limited.

Personally, I would recommend these stoves only to the self-reliant and would only buy one of these ranges from vendors who have generous return policies (an example being Costco.com's absolute-satisfaction guarantee.)

"Does anyone have a recent review on these (especially NXR)? Does anyone know the lkife expectancy on these models?"

Not sure I understand your questions. Are you asking about recent reviews of the most current models or are you asking about recent reviews from long-time owners? If the former, I do not know how one could forecast longevity except by looking at the prior models.

OTOH, the components of new models are pretty similar to those of the older ones, so if you are looking for reports from long time owners, I've had my 30" NXR "DRGB" model for going on six years now. My current review has not changed from what I've written here about NXRs over that time. The oven is still as accurate as it used to be (very accurate). The occasional clicking burner ignitor problems on mine all seem to go away after cleaning crud out of the burner ports with pipe cleaners, compressed air and/or paper clips. On repairs, I've replaced an oven ignitor (inexpensive generic part). I've re-attached an oven-light wire that came loose at the switch. The silicon feet (aka "stand-offs" or "pads") for the stovetop burner grates are slowly wearing out. I bought a pack of replacements from Adco for $3. (The shipping was twice that.)

The friends who first persuaded me to look at an NXR have had their 36" NRG model for almost ten years and have never needed any repairs. (Well, I think they just decided to dispense with the stand-off pads for the burner grates.)

The newer NXR "Pro" line of stoves have a bit better fit and finish and some added bling (e.g., LED indicator lights for the burner controls) but are otherwise very much the same as the "double-stacked burner" NRG and DRGB models. The likes of Home Depot are selling a new, much less expensive line of NXRs. These trade the double-stacked burners for common flat-capped single ring sealed burners. IIRC, I think they were going for less than $1200. Haven't seen an reviews of them, though.

The Thor Kitchen versions are available as both all-gas and dual fuel models. Both combine a pair of dual-stacked burners with two flat-capped single-ring burners. I've seen inquiries about the dual fuel versions but I do not recall anybody here reporting on having bought and used one of those. There are a couple of threads about the all-gas versions, but only three or four reports from owners. I'm guessing you've already seen those threads.

As with any older-style and "vintage" gas ranges , all of these stoves will have components that will require periodic cleaning and/or replacement. Just as an older model car would need, say, periodic replacement of spark plugs, you will eventually need to replace some ignitors for the stove top burners and the oven ignitor glowbar. Eventually, the oven will need a new door gasket and maybe an oven burner tube. Eventually, you will need replacement silicon feet for the burner grates, maybe the burner ignitor control module, etc. Most of these things are standardized parts used on other kinds and brands of stoves and so can be replaced with generic substitutes. So, how are your scrounging skills?

Or, for another analogy, think of the Whirlpool and Maytag top-loading
washing machines from several decades ago. Simple machines so pretty easy for the self-reliant to maintain but maybe harder and a lot more expensive to search out parts or get fixed when you are hiring somebody to do it for you.