Terrain hazards are something that I’d like to see more DMs do. Too often combat starts with an infinite featureless plane that allows the archers to run thirty feet away every turn (assuming they using the longbow with its ridiculous range). This might be mitigated by the DM have four walls wherein everyone then proceeds to stand around hitting each other until one team is dead. Obviously that is a slight exaggeration, but it isn’t too far off the mark. I bring this up because in the combat encounters you mention being tailored to the players, movement abilities and restrictions seem to be a thing you include. I just want to say that is awesome. Finally, I think that making characters is the best way to learn the rules for a lot of people. I know that picturing how these characters interact with their different abilities has helped me in progressing my understanding of mechanics. At the same time, building a character can be great for getting into their headspace. Their ideas, plans, training, and flaws. I find how mechanics translate to roleplay fascinating.