The PO is a bottleneck position by design, at least if you interpret “being accountable for” to also mean “do the work” (which is a misconception of the PO role, by the way). What can you delegate? What can you direct? What other business-side people can you get help from? Where can you get help becoming effective at X, Y or Z? Are you acting as a matchmaker between stakeholders and the Dev Team, or as a bottleneck and proxy conveying (and most likely accidentally distorting the understanding and intent of) messages going back and forth?