What's the "meta" like to find payment channels? That's the thing I found weirdest with LN, I needed to find a channel with enough funding. I presume the custodial LN providers just have their own payment channels?

There is a sweet spot between custodial and self-custodial wallets: "non-custodial" wallets like Phoenix Wallet or Electrum. You keys, your coins - but expect higher fees (which are still way less than CC providers or other payment processors). No need to manage channels yourself.