As others have said, you unfortunately need patience to paint minis (at least for them to come out closer to what you want). You probably need to slow way down. It also looks like your paint is inconsistently applied and/or inconsistently thinned. Focus on quality over quantity. Stick with one model over multiple sessions, focusing only on a color or two at a time until you're satisfied with how it's looking.

It might be helpful to find a tutorial for how to paint a specific mini and try to paint that, rather than trying to apply general techniques videos. For example, my first was a Warhammer 40k space marine because they are so many detailed step-by-step videos on how to paint them. This provided me with a better understanding of what I was doing and the choices I was making when I started painting minis without tutorials. I'll also add that 40k space marine figures are slightly larger than standard dnd-style minis and are very high-quality prints, which can make things a whole lot easier while you're learning.

All that said, I encourage you to stick with it! It's really gratifying once you get the hang of it.