An exchange? No, There are no US exchanges left for monero that I know of. You'd have to use a swap service (changelly, sideshift) or atomic swaps to move in and out of monero. The only exchange I can think of would be the DEX Bisq.

No, This was me testing from android monerujo to desktop monero gui wallet. It was slow.

And while I agree lightning is/was a kludge its improved dramatically in the last two years. Breez, Phoenix, and now Zeus wallets have taken care of the complexity by keeping it non-custodial and handling the channel back ups. They deal with channel balance, inbound liquidity, and connectivity by being an LSP to your wallets embedded lightning node. This covers the cons you made about it. However yes I see too many people on Wallet of Satoshi. Makes no sense these days.

Don't get me wrong I like Monero but I only use it for experimentation and speculation these days. It's slow like on chain litecoin which is good enough for web stores but not brick and mortar stores with a line of people behind you waiting to pay. It also doesn't have the vendor adoption that BTC has. Last I checked I could count gift card dealers accepting monero on one hand while holding my car keys. And no precious metals dealers that would take it.

However I do like its staying power. Most projects would have collapse by now if they were beaten on by governments the way monero has. Yet it keeps on going.