****you paid everything. that may not matter if you have a multimember LLC. the expenses you incurred could be member (partner) expenses but where would you deduct them? they would ordinarily be shown as unreimbursed partner expenses through the k-1 reporting for the entity but as of now there is no K-1. you can't deduct them on Schedule C. That would be misreporting which could create tax troubles. on the other hand, they might be expenses of the LLC that need to be split. some may be subject to the rule of IRC 195 for deductibility. The IRS rules for filing a partnership return say filing is required even if there was no income but there were expenses.
**** I could find nothing that would indicate filing an extension is the filing of a return. that's because if it is a return it's too late to switch from joint to MFS. to go from joint to MFS required filing by 4/15/2022 for 2021
