update Android 6.0 to Android 8.0 on my RCA Galileo Pro 2 in 1 I would like to update from Android 6.0 (Marshmallow) to Android 8.0 (Oreo) on my RCA Galileo Pro 2 in 1, this model is RCT6513W87 it has a 1.3 GHz quad-core processor+, with WiFi and Bluetooth.
I would like to upgrade the WiFi to dual band 2.4/5 GB 802.11ac. 


I am told that a way to upgrade is to use a Custom Recovery app like ClockworkMod Recovery (CWM) or Team Win Recovery Project (TWRP) both of these requires you to make a connection with a computer, using a USB cable.  My 2 in 1 only has one USB 2.0 port and one micro USB port for charging only. But I haven’t been successful with work with the root and app’s that give you root access.
If your wifi  chip doesn't already support dual band (2.4/5 Ghz), there is nothing you can do via software or firmware to change this - it's a function of physical hardware that was built in when the tablet was manufactured.
As far as an Android update - that is usually up to the manufacturer.  There is a menu item in settings to check for system updates.  Connect to the Internet and then select this menu item - if an update is available from RCA, then it will tell you and allow you to download and install the update.
The 2020 version of the Galileo Pro comes from the factory with Android 8.1 Go edition.