The question is, should I use bitcoin lighting or create an erc20 token?
Bitcoin Lightning Network is more efficient to use compared to ERC20 due to the cheap fee and faster confirmation since it's an L2 chain which works faster to a L1 chain such as Ethereum. Your only challenge on LN is it's not popular because only few services accepts it.
Why not choose other Blockchain that charge cheaper fee and faster block confirmation such as BSC? Binance Smart Chain is as popular as Etherum in terms of userbase. You can have tons of participants in that chain due to their reach community.
Or OP could just use ETH and Arbitrum , which is basically free compared to BSC, and BSC is basically a guarantee that no one will be investing. It's like a synonym for shitcoins, because every scammer has been using it since the beginning.