you could not interact or sell magical items to muggles?
Pretty sure they can interact as long as they don't reveal their secret, but the selling part's weirder apparently.
I did a reddit search on this and it looks like there's been some expanded lore over this kind of thing. From the topic 'Why don't wizards sell potions to muggles?':https://www.wizardingworld.com/writing-by-jk-rowling/potions
Muggles can’t make potions. So wizards and witches would need to make all these potions. It would break the International Statute of Secrecy if the Muggles unnecessarily found out about magic. Besides, Hagrid told Harry that wizards and witches are “better left alone.” Being isolated from the Muggles is simpler than Muggles wanting magical solutions to everything (even if the Muggles didn’t know the potions were magical).It’s a tough decision. One of Harry’s ancestors used magic to help Muggles. He would cure the Muggles of diseases. https://www.wizardingworld.com/writing-by-jk-rowling/the-potter-family
Draco’s ancestors used to be allied with wealthy Muggles. https://www.wizardingworld.com/writing-by-jk-rowling/the-malfoy-family
The two also use different currency, so there'd need to be a means of conversion between Galleons and Gold. At that point you might need to secure some sort of fence, someone who trades between both worlds, which sounds potentially criminal and/or niche. Even the scale of Galleons is apparently comically large:In the books, they are rarely particularly described beyond their metal, however there are several references to wizarding money and Muggle money appearing quite differently. Ron Weasley was struck by the seven sided shape of a Muggle 50 pence coin. A Muggle man described Galleons that a wizard had given him as "great gold coins the size of hubcaps". While he was almost certainly exaggerating, it does indicate that Galleons are significantly larger than standard Muggle coinage. Knuts were described as being tiny.
The topic 'The ENTIRE wizarding world would collapse overnight without Hermione Granger.' has some interesting points about the ramifications of the setting, too.
Ehhhhhh
When i said interaction i mean like clearly display magic to a muggle. There was issues with witches/wizards clearly using their power and abilities to abuse their own kind and muggles- Voldemorts father was a muggle that was given a love potion by a witch and basically raped/taken advantage of and kidnapped to conceive a child.
Loads of young witches and wizards were at some point in the book trying to slip harry love potioned chocolates. Where these powered individuals could meet a healer or a curse breaker to break them out of it, i don't see muggles having the same options.
Also i think it didn't need to be mentioned but I'm certain the farming and agriculture on Hogwarts was likely done by the house elves. I'm certain that they have some sort of agriculture going on or simply buying produce from muggles is enough idk