Gytaryst, the key to the time-vs-payoff dilemma is to make some quick-ripening cheeses as well as the long-ripening ones. A Caerphilly is ready in as little as 3 weeks. It is in the cheddar family, generally a bit tangy and crumbly. A "Lancashire" - as made by many of us, probably not really deserving of that name, but what you'll find if you search the forum - is ready in 6 weeks. So make a Caerphilly this weekend, and a Lancashire next weekend, and then make a cheddar. Periodically make another Caerphilly or Lancashire to keep cheese "in the pipeline." It will probably take you a few tries to feel confident in following the recipes, so making something that you can try in 3 weeks is a good way to gain that confidence.
As for essential equipment, here's my list:
A thermometer with good accuracy in the 80-130°F range
A stainless-steel cheese "ladle" (basically a shallow-bowl slotted spoon)
A stainless-steel pot of suitable size
A curd knife - which for me is just a large-size cake decorating spatula, not very expensive from Amazon
A stainless-steel colander - if you want to make 5 or 6 gallon batches, you'll want a large one - I got mine on Amazon, again not too expensive
Cheesecloth or butter muslin (the latter is a "finer" version of the former)
One or more cheese molds - which can be made by poking holes in inexpensive food containers if you don't need to apply overly high pressure (this is a cheap way to get started)
Some sort of press - you can buy presses of a variety of styles, but I recommend looking at the many plans on-line for a dutch-style press - easy to make (can be as easy as a 2x4 hinged to a wall, with another 2x4 hinged to it to act as the ram, and a jug of water as the weight)
Note that the press is not needed if you make certain types of cheeses, such as the blues, cams, brie, etc.
If you really want to go straight to the 5-gallon size, you will probably want to get an 8" diameter cheese mold. For a 4-gallon make, which is what I mostly do, I use a 7" diameter mold made from a recycled bucket of the appropriate type of plastic. Before that, I mostly made 3-gallon makes, and my primary mold was a 6" diameter food storage container, again recycled from its former use.
Note that, as I have gained experience, I have moved to using direct heat. This is possible due to the way my stove works with the heavy-bottom stainless pot that I use. Before that, I heated using a "double boiler" approach - suspending the stainless pot in an inexpensive water-bath canner (basically just a very large pot), so that I heated the water, and let the water heat the pot.
One last item: not essential, especially at first, and maybe never depending on the kind(s) of cheeses you make ... but one of the most helpful, though definitely the most expensive, bit of equipment for me has been a decent pH meter. You need one that is really accurate, and one that can ideally test the pH of the curd as well as of the whey - i.e., not just limited to liquids.
Welcome to both the forum and the obsession hobby!