I'd like to know if is it possible to maintain a specific IP address in a specific city and/or state (thus, maintain a specific exit node), so that when I close the Tor browser and then reopen it, I still have the same IP as last time?
that's perfectly possible, at least if there's an exit node in/on that particular city/state/country/continent (you'll need to do your research as to where exactly the exits are physically located yourself), but quite discouraged, as for certain scenarios it makes attacking you easier - if you still want to go down that route, see https://www.torproject.org/docs/tor-manual.html.en#ExitNodes
A list of identity fingerprints, nicknames, country codes and address patterns of nodes to use as exit node---that is, a node that delivers traffic for you outside the Tor network.
there's also the .exit notation which would enable you to choose an exit based on using a special domain - https://www.torproject.org/docs/tor-manual.html.en#AllowDotExit
If enabled, we convert "www.google.com.foo.exit" addresses on the SocksPort/TransPort/NATDPort into "www.google.com" addresses that exit from the node "foo". Disabled by default since attacking websites and exit relays can use it to manipulate your path selection. (Default: 0)
not sure how aware tor browser is about content, i believe it breaks a lot of things and isn't particularly safe to use