Why doesn't anything sync?

Hi.

I’m new to SmartThings and only use the mobile app. I don’t have a hub. I like the fact that you can create true conditional automations unlike Google Assistant or Alexa and can create more variables than IFTTT. I have Philips Hue lights around the house, TP-Link plugs and also some Smart Life products.

The problem I’m having is that SmartThings doesn’t seem to keep in sync with anything. If I have Hue lights on in SmartThings but then turn them off in the Hue app or GH or Alexa, SmartThings still thinks they’re on. And the status never changes. It’s the same for TP-Link and Smart Life products too - SmartThings only seems to be correct if I only make changes in SmartThings or go into SmartThings and correct the status.

Is this a known problem? I’d expect SmartThings to be syncing with the Hue/TP-Link/Smart Life apps every couple of seconds like GH and Alexa do. They are talking to each other as incidentally when I make a change in SmartThings all the other apps update themselves straight away. It’s as if SmartThings can’t listen.