Prusia Mk4, Ender 3 both relatively affordable machines with cheap materials. I see them a lot on the hobbyist market.
In my experience there is no printer that just *works*, you will have a lot of testing early on and they can always be finicky for seemingly no reason.
Even the industrial grade Stratasys that I've used in college and at work are known to have their fair share of issues, despite costing $40k and $20k respectively. Oh ya, the material for those is also like a couple hundred dollars per roll.
I have a friend that has a PRUSA and swears by it. In my first look, I like that you don’t need to have it tied to the cloud. Bambu has some attractive features/pricing, but from my reading, you can’t run w/o being exposed to the Net. That’s a non-starter for my customers. Can’t blame them based on current shenanigans.
Saw a vid of the new three arm PRUSA HD90. Prints a good variety of eng plastics. No price on the website and no response from them after several days. I saw one comment on a forum to expect $10,000. My volume can’t support that capex with the reasonable turnaround that Xometry provides me … w zero putzing with an in house machine.
For what it's worth, we run the Bambu X1C through local network only; no external connectivity.
My old DoD group just picked up a P1S that they have air-gapped as well.
I know that our X1C is WiFi only, I'm assuming that the P1S is probably the same.
Ours is connected to a local network to enable remote control from my desktop, but definitely not required if you just want to transfer files with physical media (SD Card). I believe that my DoD group physically removed the WiFi module from their P1S (no idea how easy it was to get to). I think that the X1E has a RJ45 jack, that might be worth looking into. Not sure what your needs are for offline-only, but if you're manufacturing ITAR controlled items, your ISSO will still probably require you to maintain a physical air-gap to be compliant.
I will note that we had to connect to an external network during the initial setup period for our X1C, I think for a firmware update.
I have nothing bad to say about the Bambu printer, it's incredible for FDM. My main use-case is fixtures, tools, and replacement parts. I typically print with PC or PAHT CF.