This isn't bad as a starting point!
There's a hall-of-mirrors bug on the stairs with the vials. Also the powerup placement isn't great- Having a keg directly under a solo point isn't good, and having a health pack next to the high point isn't either, as health packs take you to 100 health in sdom. I'm unsure about the belt location, it seems like you can easily get shot dodging to it from above. I was surprised to see boots on this map, because I'm not sure if it needs them at all. They're kind of interesting to see, but they certainly shouldn't be so close to an amp, which is right next to a point.
The biggest problem here is the high point, which is only accessible through 2 corridors. As long as the player can keep a stack of some sort (even just a health pack), they can easily hold the position just by standing on the point and ducking into the health/ammo nooks. I think this top area needs to be reworked somehow, although I'm not sure how. For sure move the keg to a riskier location (but not out in the open), so that you have to walk away a little from the one point to get to it. Delete the health pack next to the high point and move it farther away after redoing that area somehow. Perhaps delete the boots and do something different with the belt.
I also think the low point needs some pillars down low and additional powerups in the corridors outside of it (that players have to walk to). It could be more like the dungeon point on campgrounds that way, having to walk to the health or belt and briefly abandon the point. At the moment it's a little too open (campgrounds dungeon is a curved room that provides a little cover).
Basically you want powerups to be accessible enough that they're important, but not so much that they're free for whoever's on the point. You don't want purely open, very dm-heavy points, but you also don't want very enclosed points that are too easy to hold positionally. I like the idea of a smaller, uniquely designed map like this in general