Power meter experiences with lag

I currently have a Stages power meter and the power readings to the head unit or mobile take about 7 seconds to update. That’s 1 second power to a Garmin 530, or iPhone 14 Xert or Stages own app. This means that I can’t use my stages power meter on my trainer and it reads lower than my trainer so I don’t know my corresponding XSS from outdoor rides, nor if my zones and LTP is correct…

I have to warranty the Stages as it’s got a problem and not calibrating and honestly thinking of splurging on a new Sigeyi PU.

What are people’s experiences of Stages and Sigeyi power meters? Would I be wasting my money? I’ve tried troubleshooting my current setup and sought advice previously but never to any avail.