I've got many tips, don't want to bombard you but you did ask.
The biggest tip would be; If you want your map to be featured on the server you will need to build it on Java Edition. However if you're doing this for fun then that is okay.
But more on the build, your palette choice isn't the most aesthetically pleasing, try using blocks that complement each other, because you end up with a flat looking build and it just doesn't look exciting. Maybe consider your theme, think what you believe is the theme of your map and look up some concept art. I tend to use pinterest. Also consider your build from the player's perspective; placing lots of flowers limits where players can place blocks, in turn, limiting their possibilities. Also flower spam doesn't really look the best imo. More on player scale, the underground section of the map is very cramped, think of this from a pvp outlook, it doesn't seem optimised for pvp at all.
Also try to mix up your block choice, using blocks that are of similar colour work amazing for texturing your build.