It's difficult understanding how many VM set top boxes you have. Did you previously have two V6 boxes, but now only have one 360 box? Or do you actually have two 360 boxes and two 360 remotes?
I only have one box. My second TV has, for several years, been attached to the box (previously a v6) by a HDMI cable it worked well with the old controller.
If you only have one VM TV360 box then it's not possible to control a second non-existant 360 box. If you have a multi-room subscription with VM then you would be provided with an additional box to attach to your second TV.
Your box should stay in standby mode and shouldn't switch off every 24 hours providing if it has received an interaction from yourself such as changing channels or opening apps for example at least once in each 24 hours period from the last interaction.
You have 3 choices.
Fast start - the 360 starts quickly but is less energy efficient
Active start - more energy efficient than fast start but the box takes a little longer to start up
Eco start - the most energy efficient and probably the one you're using. It uses minimal power but takes a while to start.
You need to have the box set to Fast start or Active start and don't turn it off at the plug and then it should stay in a Standby mode where it can still record and receive updates. (Setting it to Eco start is a bit like switching the box off)
Back to the TV Go app. Once opened there is a head and shoulders ison in the top left hand corner. That is the profile button and clicking on that allows you change from the shared profile to any other profiles you have set up.
Also on the top right hand side of the TVGo home screen is an icon depicting a TV screen and remote control (immediately to the left of a magnifying glass icon) Clicking on that allows you to select and connect to any additional TV360 boxes that you subscribe to.
If you don't subscribe to a second VM TV set top box then if you have a computer/laptop you can connect that to your second TV via an HDMI cable and open and use the browser version of the TVGo app (virgintvgo.virginmedia.com ) so you can watch most channels and programs on your second TV.
Re WiFi
With solid brick walls the WiFi is not wonderful - I have three pods and the signal strength is just rated as just about OK on two of them.
The actual wifi signal will depend upon where you actually place the pods. There's no point placing the pods in a location that already has a very poor signal. It needs to be placed in a location where the signal is stronger so that the 'stronger' signal will reach further. See <this post> for an explanation
Have you run any checks via the Virgin Media Connect App?
Once the App is open select the Broadband option from the bottom menu. This will display the My Devices page. Click on the My Network tab/icon. This screen will show you how many devices are connected to the Hub/each Pod. Tap on a Pod for more information and then tap Connection from this list.
If fair is showing, this indicates that the Pod(s) you already have may not be in the optimum place for performance. It is advised that you choose another location in the home, allow 2-3 minutes for the Pod to reconnect (wait for the light on the Pod to stop flashing) and then re-open the app and try again.
The app can be refreshed from the My Network or My Devices page by dragging downwards from the center of the screen. Tap Let's improve it to progress to the Refresh WiFi screen. (Note: Refreshing the WiFi can take up to 15 minutes.) Placement Tips can be used to help you decide where to try placing the Pod within your home.