The best way to find out about Tor (Browser) is to try. Android APKs are available, likewise for Linux, Windows and Mac. iOS is a different story.
FYI, the downloads are for the browser, not for standalone Tor or Orbot.
But yes Tor has drawbacks. It is not as fast and is more likely to get blocked than a VPN or direct connection. Compare Tor Browser and Mullvad Browser + VPN with the same browser settings.
Guard nodes do not know the origin and the destination of the traffic, guard nodes are simply nodes that are used to to enter the tor network, and are chosen to be used for the coming two months.
Guard nodes can identify the source because they receive a steady stream of requests from the same IP address, provided no proxy is involved. A compromised guard node and an associated compromised exit node can indeed reveal the source and destination of the request.
A semi-static guard node does somewhat affect the three - hop architecture because sources will have the entire duration that guard node is static to correlate your traffic, making the security of TOR more accurately somewhere between the anonymity possible with two volunteer run nodes and three volunteer run nodes. We don’t know the full analysis capabilities of nation states at this point, but it does seem like something that would still be only applicable if you’re being specifically targeted by a nation state.
This is one of the reasons it can be beneficial to connect to TOR through a trusted bridge, proxy, or VPN. Doing so will most likely make correlation more difficult. Don’t connect to TOR from your home network and expect that to be a failsafe method of browsing anonymously.