Cryptocurrency

And what about the problem of force closing channels and causing the people to pay the fees on chain which can be quite expensive?

On-chain fees are like $.50-$1 most of the time. This only matters if you operate a routing node. If you do, it's something you need to take into account and plan your channels wisely. There's no incentive to force close, non-forced-close is cheaper for everybody, so forced close only really happens if the other node just goes awol for whatever reason. People who are using "regular" lightning wallets never have to worry about this since a lightning service provider (LSP) handles everything. The number of LSPs continues to increase over time and wallets are talking about adding the ability to automatically select LSPs based on published pricing. Importantly, LSPs do not custody funds so there is no rug risk there.

The other situation that gets talked about in relation to channel closes is if a malicious party broadcasts an old channel state to chain (and you have to step in and say hey no actually this is the newest most correct channel state). This is an attack that exists in theory but in practice there is anti-incentive to do it. You lose funds trying it and most lightning wallets and all lightning service providers (LSPs) automatically monitor the chain for this so your chance of actually accomplishing this are basically zero. I have never seen this happen in the wild nor have I ever heard of it happening.

Zeus gets a new version like every month and it's open source. There's plenty of FOSS lightning wallets. Electrum is a good desktop one.

It sounds like you know a good deal about the tech and are interested in it. Encourage you to research more on lightning as well as Ark.