Hey there!
I noticed a lot of factories currently can't be used in Create: Above and Beyond due to other mods, so I decided to find something myself.
I just wanted something that was multi-layered that I could work out of, I am not much of a builder myself.
I found a simple structure that only uses vanilla blocks from the Heliopolis City mega project (V.0.1 MAP) (https://www.planetminecraft.com/project/heliopolis-city-mega-project/) that I could use so I decided to share.
I asked HeliopolisCity (https://www.planetminecraft.com/member/heliopoliscity/) and he said he didn't mind if I shared it, all credit to him.

I have added two different schematics: the original and my modified version. This is the modified version, here is a couple of things to keep in mind:

- Uses clear glass panes
- Uses chiseled bricks (Bricks)
- Uses brass lanterns
- Leaves out glass in the middle windows out front to get in and out
- Fixed windows on the sides
- Floors/ceilings/walls are one block deep, would need to be modified to hide shafts and such
- Design is based around having flight (Gale or the feather charm) - No stairs, would need to be added in
- The sides are flat, no detailing on each
- Requires A LOT of blocks. I needed to set up 5 (4 on the side, one below) Cobalt barrels around the cannon, and still had to let it run and fill it as it goes

I recommend pasting the build of your choice in a creative world, modifying it to your liking, and then setting it up in survival.

Block List:

Andesite: 2180 (34s + 4)
Block of Quartz: 2882 (45s + 2)
Brass Lantern: 80 (1s + 16)
Bricks: 3733 (58s + 21)
Clear White Stained Glass Pane: 1798 (28s + 6)
Granite: 5722 (89s + 26)
Iron Bars: 160 (2s + 32)
Polished Andesite: 2069 (32s + 21)
Polished Diorite: 2949 (46s + 5)
Quartz Pillar: 844 (13s + 12)
Quartz Slab: 185 (2s + 57)
Quartz Stairs: 880 (13s + 48)
Sandstone: 3220 (50s + 20)
Sea Lantern: 692 (10s + 52)

Hope it helps!