1 - You can either store sats on Lightning by running your own node. You're keeping sats in a hot wallet though so it will never be as secure as keeping your Bitcoin in cold storage, but as long as you secure your node well and safely store your seed you should be fine. The alternative is to go for a custodial solution by utilizing something like Muun, WalletOfSatoshi or some other reputable actor in the space if you dont feel like running your own node.

2 - The Lightning Network holds tremendous potential. It effectively solves the variable time and cost a Bitcoin transaction involves El Salvador's Bitcoin onboarding is pretty much completely based on Lightning (and level 3 solutions). We are still in the very early days of Lightning Network adoption though and there are several significant technological developments in the pipeline such as Pickard Payments / split payments that will make LN scale a lot better and handle larger transactions more smoothly. The LN hasn't seen the hockey stick level of adoption but I'm pretty sure it's coming. It's pretty much the only way for Bitcoin to be used for everyday payments. Furthermore, what Strike is doing shows that you can utilize Bitcoin the network without even thinking about bitcoin the asset, allowing users to essentially transfer dollars or any other form of currency over the Lightning network. If you don't yet understand the difference between Bitcoin and bitcoin I recommend reading up on that.