Looking for admin and/or recordkeeper that can handle plan assets consisting of just single stock positions

I’m an advisor creating a 401k plan with individual brokerage accounts that each have a unique portfolio of stocks (not as an SDBA- these managed accounts would be considered plan assets), and haven’t been able to find platforms that can support this. I’m building out the participant and plan sponsor web portals to get the needed inputs and convey the investment choices, and have direct API communication with the custodian, but need to outsource the administrative functions. Anyone with experience in this?

Are you looking for someone to handle the actual TPA administration (compliance testing, contribution calculations, annual reporting, etc) or someone to strike a daily price for a unique portfolio (similar to a collective trust account)?