Players are generally resistant to changes made in a game. When you release a game the players that keep coming back are the ones that liked what you’ve made. Those that don’t like it won’t cone back. Many of them won’t even try for a new game mode.

Even if you released with all planned modes your player base would likely fracture into the modes they prefer, but not evenly. Eventually you’ll have to prioritize one mode over the others and you’ll pick, not your favorite mode, but the mode with the highest player count. This will lead to bugs not getting addressed in your less popular modes and player counts eventually falling off.

Consider COD and Fortnite. Each are massive franchises with huge player bases and multiple modes, but there’s really only one or two modes that people play (and those games are produced with massive investments. Hell, PUBG even has occasional seasonal modes–but it’s not getting huge numbers of non-pubg players you boot the game and the core player base is sticking to the mode they play the game for.

My advice here is to pick one mode. The one mode you most enjoy and build that. You can then build a community around people that like the same gameplay you do and your enthusiasm for that mode you enjoy will help that community grow.

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You mention you are still new to game Dev. What have you built already? These are all ambitious projects, and it you don’t have the relevant experience yet will be a VERY difficult task. I’d advise making your first couple of projects really small to get a feel for it and learn incrementally. This will help you gain the requisite skills and delay burnout. If this is your first real big project and you’ve done nothing with multiplayer before you’re gonna have a difficult time.