Hey!
Actually, no. I also used frame-by-frame animation for two of my 2D projects.
I also know there's a 2D rig-based system that's less complicated than 3D. I haven't used it yet, but I can create a small demo if you plan to use it specifically.
Look, there're some different approaches to animation in games:
1. For pixel art, you switch pictures fast, so the player might say the same character moved. Each small image is called an animation frame. 
2. Fully hand-drawn animation means that you're going to need all the frames hand-drawn. Then you scan each one to use it in your game the same way you use pixel art. Very few games follow this approach. Like "Cuphead" or "Hollow Knight". 
3. Another approach is to use a rig on the character. For this one, you want to scan the art you've got and redraw it in vector/digital paint. You need its head, torso, arms, and legs split, so the animation library can move them independently.
I can vectorize your hand-drawn character if you have one, and create a 3d scenario animation inside the engine. I can only use ready art for the 1st and 2nd approaches; I'm not an artist )
So what do you need?
Thanks for explaining the concepts of animation to me; I’m a bit of a layperson when it comes to the artistic side, as my field is programming. It would be great if you could create an animation for my character—he’s a hand-drawn 2D character; in fact, the entire world of our game is in 2D. The image below is a prototype of our main character; it lacks color because it is merely a prototype, intended to test what the character's visual design will be like.
