There are multiple recebt threads already on this topic asking your questions. Look for tgreads with VTT in the title or with online play or with similar titles to your own pithy one.So the Discord theater of the mind based approach is the first thing I've hit on.
Can someone with experience review Fantasy Grounds and/or Roll 20 and talk about what it takes to make it work, and work better than just a chat room?
Last sunday my group used Roll20 for the very first time. I took me a few hours to familiarize myself with the program. Fortunately it comes with a very good tutorial. We still used Discord for voice chat, but everything went smooth. Although roleplaying isn't the same without being able to see each other's faces (we don't use webcams), playing online offers the advantage that battles are a lot easier to follow for the players. Players can scroll the map around as they please and zoom in and out when needed. Roll20 also makes it very easy to use fog of war, to reveal or hide various things from the sight of the players.
Lessons learned: Use Chrome for Roll20. It is a little bit buggy on Firefox.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.