Questions with Netgear Nighthawk travel router

Hi all,

I hope this finds everyone safe and well.

I purchased a Netgear Nighthawk M1 router, and couldn't be happier with it. This thing is incredible!

I have four (hopefully quick and easy) questions, that I was hoping I could get some feedback / answers to.

1.Do external Antennas boost WiFi signal? I have a small unit and the reception (WiFi) doesn't seem to make it to my spare bedroom (office). 4G reception, however, is perfect. Do the plug in antennas boost WiFi, or only 4G signal, or both? Does anyone have any recommendations for a good set?

2. Can I turn off the blue LED? Sometimes I take the modem into the bedroom so I can use the Google Chromecast. I know it's bad to have WiFi and wireless in the bedrooms, but it doesn't reach from the kitchen. The blue LED drives me bonkers. Can I turn it off? I can't seem to find it in the app settings.

3. Is it bad to leave it running 24/7 with the battery in? Can I take the battery out and use it 24/7?

4. Can I use a WiFi extender if I have my SSID set to hidden mode? I have a TP Link AC750 travel router, but I can't seem to add a hidden SSID to extend the WiFi range. I was wondering if maybe this is not possible.

A massive thanks in advance for all your help, tips, suggestions, etc.

Have a great weekend.