there are any number of ways to get infinite ore. None of them directly in the game, because this bypasses the design, but all are very easy to do.
the easiest one for me is just to have a chest of whatever you need on another world. Stand where you want the material (usually by a chest on the target world) and log out. Log into the world with the materials. Gather them into your bag, and log out. Delete the stored world file and replace with its .old file and the material restocks. Log into new world. Dump into chest and consume. Repeat as necessary. This has the drawback that you have to actually gather some first, though just a single bar (you can get from fishing now) will fill a giant chest in short order if you dupe & double each time, 1-2-4-8-... after only 9 or 10 cycles you will be set.

as noted you can also use cheat codes, but you have to start the game with a flag to enable those and I don't like them; carelessness can damage your world.

you can probably find or craft a mod that does something snarky like refine 30 bars from 1 ore or gives iron from the obiliterator or something like that.

there are probably many other ways too, but those 3 should get you there.