IDE - unusable!!!

Ahh right, so:

Bad

1. Physically disconnect
   
2. Physically reconnect
   
3. Disconnect and reconnect via the button and no device appears
   
   

Good

1. Physically disconnect
   
2. Click disconnect button
   
3. Physically reconnect
   
4. Click connect button
   
5. Device Appears
   
   

This is definitely the issue with Chrome Serial. It was reported over a year ago - I just tested with the Chrome Canary (one of their latest builds) and it's still not fixed I'm afraid.

Do you think it's possible that you have a dodgy connection to the Pico? If it disconnected and reconnected, it'd explain all the trouble you're having?

You might find that putting a sticky label or bit of tape on the back of the Pico's connector will increase the width and make it more reliable.