You don't need fancy animations or water that looks like water to work on the game design.

Use place holders for everything

Agree with this. Sounds like you want to prototype game designs more than code/utilize final implementations. The standard advice you'd get in game dev is to use super low production value assets to prototype. People even often "paper prototype" or use other completely non-digital media.

I agree with the sister comment to parent that suggested something like Game Maker. Those tools are simpler and more usable out the box than game engines.

If you want the feeling of completing a simple game as you go, and seeing your (near-)final implementations of elements as you hammer them out -- that's fine as a learning exercise. It will probably be inefficient (as you may change you mind about things later on that you already spent a bunch of time implementing/polishing), but it can be a cool way to learn. However, for that, you may run into what some other comments are saying: you'll have to figure a lot of custom stuff out as you go.

Edit: There's a good series[0] where a game critic / indie game dev makes 12 games in 12 months. He uses Game Maker Studio 2 and the episodes go back and forth between concept/design and execution.

[0] https://www.escapistmagazine.com/v2/category/v2/yahtzees-dev...

Whiteboxing/Greyboxing/whateverboxing is one of the most important processes that all too many hobbyists don't do, which causes them to burn out on gamedev. They want to _see_ everything working with how it looks in their head, but in reality the game mechanics vs. visuals are very different skillsets that can take a lot of time to master. I would recommend most new gamedevs spend all their time using just default objects in their respective engines. Literally just white/grey shapes that act on user input. If the mechanics feel fun with whiteboxes, they'll feel more fun with actual models/sprites/whatever. But on the flipside, you'll never know if your mechanics are fun if you never make them because you're too busy worrying about water animations.

Game Maker is a full engine. It's just more streamlined than most.

> It'd be nice to be able to create a character and just attach preset behaviors: walk like Dota, add jump, etc

You can already do this via the Unity asset store.

But I'm guessing in addition to having your dream engine/working environment, you also don't want to pay a dime for it.

They do say you get what you pay for.

I have searched in the Unity asset store, and there is either not what I need, or what I need is in several different packages that aren't seamless to use together, or the cost of everything is more than my monthly salary (non US here)

> But I'm guessing in addition to having your dream engine/working environment, you also don't want to pay a dime for it.

Before Unity came out the same could be said about people wanting a more accessible engine, no?

I'm fine with Unity's and Unreal's pricing models, I just want a more creator friendly game editor that isn't Roblox

Really?

https://assetstore.unity.com/packages/3d/characters/moba-mov...

Come on, man.

I have already done myself what that package provides

It seems to me you would be better served with something like GameMaker.

Sorry dude, learn the skills and get it done