Bombie,
Don't want to get your hopes up, but:
Picked my 2023 Whyte e160 up last weekend. Didn't have time to tune suspension or set up cockpit. Couple of local rides, no issues. Started tinkering with cockpit/suspension few days later. LED remote wasn't where I wanted it so - unplugged the cable, moved LED mount. Plugged cable back in. Attempted to turn on - same issue as you - leds chase up and down but no start up (or connection to Flow app). Realised it must be due to not plugging cable in correctly, took a closer look, hadn't pushed it back in until it 'clicked' into place. It takes a fair bit of force.
Have you had yours apart and now have the same issue possibly? I suspect the blue leds chasing up and down but then switching off could indicate a connection issue with the LED module. On the underneath of the cable is a white mark which lines up with one on the the port, take care and check it hasn't somehow been caught and loosened. Hope this helps bud.
Tower
Edit: apologies, just spotted this was July, not August. Presumably you got it sorted.