So those are my tips. First of all, the map is TOO small. The map doesn't need to be huge, even most of my maps are pretty small, but map for 1 minute is too small. Add light source under slimes, add grass and flowers on grass block, add small mushrooms on mycelium, add ferns and sweet berries on podzol, don't use many floating blocks, don't place blocks on walls, add seagrass in water, add repeating, always active command block with /effect give @a minecraft:saturation infinite 0 true, add dead bushes on sand.