They are popular because they were permissive and dead easy to use in… 2008 or so. Indie studios adopted Unity, many went on to great success, and it is now a product with a huge userbase, tons of tutorials, and an industry full of experienced Unity developers.
Unity is successful, entrenched, known, and makes money.
And this is the worst possible situation for a product to be in. The term is “enshittification” and basically means the owners are incentivized to sell out, while new owners are more incentivized to add new ways to extract value than to improve the product meaningfully. This is a death spiral that no products recover from.
It’ll just get worse until in several years all that is left are some patents bought by a patent troll who sues the everliving shit out of anyone still using Unity.
Anyway: Look up Godot. It’s a modern version of what Unity was when it was young and pretty.
If you pick it up again at some point, my recommendation would be to turn down enemies, increase resources, and just ignore most of the tech. It is there to give you flexibility, and many people’s first win had no trains, no nuclear power, low tier belts, no artillery.
Oh! Same order for me. Bloodborne first, which I managed to bull through after a lot of effort. Then later ER which I got quite stuck on and took a break from.
While painful, it makes sense to push cliff explosives into later game. Cliffs are completely irrelevant in the current game, as you get the tech to blow them up so soon that they don’t manage to affect your base layout.