In StarCraft Brood War there were normal maps, which were mostly played 1v1. That was the "true" game - it was fun but also quite difficult.
Many players played for fun, so they would play team games e.g. 4v4 where skill still mattered but often the results depended more who you got on your team (I think that to a degree this is why MOBAs are so popular - in theory you get close to a 50-50 winrate, or at least win like 30% games even if you are bad).
Some players enjoyed a map called "Big game hunters" (or BGH for short) where you didnt have to care much about resources - they were abundand in your starting location. So you didnt have to think about building new bases (big part of regular StarCraft gameplay). In fact even more simplified "fastest" maps were made, where resources were stacked near every player's starting point and the map was basically a square with some choke points. The layout was simplistic too. It could still be fun and better player wouod still win. But again most players played team games like 4v4 where you could always blame your loss on your team.
Then the players played a map called "Blood bath" that was incredibly small - so games could be shorter (few minutes), since players would often "rush" (=attack quickly) each other to win or lose fast.
Those simplifications that removed part of the main game loop were still fun. Often by making the game a bit easier. (Although I remember some challenge between "regular" players and "BGH" players wherr BGH players won, since they know how to play BGH and they were good enough to win on a regular map).
Then StarCraft Brood War had thousands of custom games, which had deep ability yo customize the game and a primitive programming language - that allowed to completely change the way the game worked. MOBA genere, turret defence - all came from StarCraft Brood War custom games.
I think that apart from Warcraft3 no other game allowed so much custom maps from the stock (without mods). In Starcraft 1 and Warcraft 3 you would just download the custom map and play it.
Starcraft 2 never managed to get custom maps as popular due to Blizzard's mismanagment: no custom game list. Also Blizzard was probably trying to monetize custom games/maps but failed.
Designers often ignore that (1) there are bad players that still want to win sometimes even due to sheer luck (2) some players want relatively braindead simplistic fun.
I think in Fortnite they have a popular custom map that is a big square arena where both materials and ammo are infinite. Again a simplification, but at the same time a lot of the essence of the game is still there (shooting and building).