Whew, that's a lot of responsiblity to think anyone would be following along on this journey and actually think I have any idea WTF I'm doing! I'll do my best to give you some multifaceted advice, because what the right path to take in gamedev has to be the most random, "Who the heck knows?" sort of question EVER!
I don't even know what the heck I'm doing, so I feel a little weird giving advice from the position of abject failure!
Ok, i'll try to just be straight up, and bear in mind, sometimes the best thing you can do is just be stubborn and follow something if it's really calling you, follow your gut. It's not a guarantee of success, but it'll likely give you your best chance or at least be what you want to do stumbling down this rocky road.
My first bit of advice would be don't do multiplayer, eveyrone wants to do multiplayer until they start making a multiplayer game, to say nothing of the hidden pitfalls of your game just never being played since no one can find anyone to play a round with.
Multiplayer tends to be an evolution you make when the time is right, or at least that's how it used to be back in the day before everyone and their uncle was chasing some break out multiplayer hit right out of the gate for all the wrong reasons.
If I could go back in time and do something diferent after being a stubborn goof ball just pursuing SeaCrit with reckless abandon, it would be to make an idle game.
I friggin' LOVE idle games, and I think they have a lot of room to grow and evolve and the bar for making a break out hit idle game is SO much lower than to make a popular 3d beat 'em up.
https://cheerfulghost.com/games/candybox2
Too often as solo devs just starting out we want to make a Science based dragon MMO, but there is so much more room to try other things, inventive things with less limiting overhead of fancy graphics and netcode , and they're also easier for people to try and to put up on various websites.
The best advice is probably to just run and don't do gamedev this place is a meatgrinder, and the industry is fallen apart, and the storefronts are all locked up, and flash is dead, and in every conceivable way the asshole deep pockets could make this hellscape harder to succeed in, they have done so.
But if you're like me you just really want to make a game and have a damn the torpedoes mentality.
I wrote this article some time back, but it still holds up:
https://code.tutsplus.com/cubes-vs-space-marines-making-a-great-game-in-your-bas...
I think I've got some pretty decent insights in there about how to get started on this crazed journey.
Everything in gamedev is a contradiction. If you spend too much time on one project, you might be putting all your eggs in one basket and waste time on a game that's a dud. You also don't learn broader skill sets or force yourself to go through the motoins of retooling workflows in a wax on wax off manner. Jump from projec to project and you wont develop the habit of pushing things to actual completion, learning to set your standards high and invest into something you're truly passionate about. You kinda learn to chase that feeling of butterflies in your stomach like someone that goes on too many first dates, and then wakes up at 35 and realizes they're old and alone...
But in this era of game jams, I do feel like you can be a bit of a diamond in the rough if you learn to actually stick to something and give it the time these systems demand in this era of instant gratification!
At the end of the day, I would say just do what really calls to you. If that's multiplayer, stick with multiplayer, if it's an action RPG make that actoin RPG.
The trick is finding a way to make it doable, how do you simplify it? Because the truth is, that this industry learned the hard way, is the player won't know all the manhours put into something, they don't care how many years you put into assets, and rigging and all that jazz.
All they care about is the ratio of Secret Sauce you can put into every bite of your game. So for all our dreams of making these high end games with fancy graphics and assets and high art, a lot of players just wanna play match 3 games with images of candy in it!
Finding success in gamedev will NEVER be easy, the various pitfalls just trying to keep motivatoin up gets to be soul crushing after years of time, to say nothing of fickle player bases and chaotic markets, and industry manhandling.
TLDR: My advice would be find a game that's successful, that was RELATIVELY EASY TO MAKE, that you're passoinate about and you think you could be called to put your own spin on it.
When you think about it, there are genres of hugely succesful game that have only scratched the surface of what's possible! Idle games, games like peggle, card games, heck look at Balatro! Balatro is a fantastic example of taking a game that's easy to pick up and play and already has universal appeal and it throws a whole new layer of digital depth to it!
I do want to stress though, that you're probably asking the wrong guy as I have no idea WTF I'm doing and haven't had even the slightest bit of success after all these hard fought years, but I'm really stubborn.
So I would have WAYYYYYYYYYyyyyyyyyyyyyyyyyy more confidence in explaining how to FUCK UP your game development ROFL.
But there it is, that's my attempt at helping you course correct to a project that might suit you.
OH and I would recommend you check out Jonas Tyroller on youtube if you haven't already, that dude is AMAZING for helping other people find the right path of making a game, and the dude walks the walk too, which so many people don't appreciate. Guy is a total work horse and puts the hours in and deserves every bit of his success, I don't know where he finds the time to make YouTube videos on the side, I spend most my free time on youtube watching people bitch and moan about modern marvel movies.
Anyhow! Don't be shy about any follow up questions you might have Antonio. Hope this helped you in some way shape or form!