Its called money walls many people have been wanting it back it was removed on cubecraft so I dont think you will get copyrighted it was my favorite minecraft minigame until they removed it if you could remake it I would definitely play it.But if cubecraft added back you would probley have to delete it and I said might so not 100% and what is money walls
If a server owner can add some more ideas to the table and fix the previous bugs it was experiencing, then it would be pretty popular, but it wouldn't be as popular as the skyblock takeover that Hypixel has created.
Skyblock is the meta right now, so much so that people outside of Minecraft have made their own versions of skyblock.
Even Bedrock Edition servers have implemented Skyblock in hopes of activity, but honestly, it's not going to change much because of the poor quality these Bedrock Edition server provide.
It's not a bad idea, but Skyblock is in the most popular gamemode right now and until it dies down or people start feeling more nostalgic, it won't be at its full potential.
Wall minigames are not at its peak as well. Just some thoughts to note, but quality and fun is everything.