I would expect that to activate the immune system. "the unique components of mitochondria, when exposed, reveal their prokaryotic history and are recognized as foreign by innate immune receptors triggering an inflammatory response." https://pmc.ncbi.nlm.nih.gov/articles/PMC6218307/
Maybe if you suppress the immune system, introduce working mitochondria, and then stop taking the immunosuppressants, any mitochondria that are still outside cells get cleaned up and the ones that got absorbed are shielded and can do their job.
Maybe if you suppress the immune system, introduce working mitochondria, and then stop taking the immunosuppressants, any mitochondria that are still outside cells get cleaned up and the ones that got absorbed are shielded and can do their job.