Well for 2023 you can test otherwise excludable separately so you shouldn't have an ADP testing failure.
For 2023 you'll need at least a top heavy minimum for the employee and a QNEC for the missed deferral opportunity. But you should be able to self correct under recent IRS guidance and the most recent EPCRS procedure.
For 2024 the solo-k should just be restated, no need to open a 2nd plan. Look at the EPCRS procedure for any additional missed deferral opportunity than may be required.
You are also going to have 401(k) testing and TH minimum so you might want to consider adding a 3% safe harbor non elective prior to November 30.