2021 formed LLC functioning as a partnership. Bought a house in 2021 and sold it in 2022. Was I supposed to file a form 1065 in 2021 even though we had no income?

A domestic partnership must file an information return, unless it neither receives gross income nor pays or incurs any amount treated as a deduction or credit for federal tax purposes

I don't see what buying a house has to do with forming a multi-member LLC. Did the LLC buy the house and then sell it? If so, then you probably have a reportable financial event.