I'm betting on ⚡ organically becoming the sat symbol because:

1️⃣ Zaps!

Even if we move to mint-zaps, this will still be the zap icon and the thing people see every time they zap any kind of sats. Also, the freedom tech that will take BTC mainstream will very likely be Nostr apps and have zaps.

2️⃣ It looks f*cking cool, represents POW and energy like nothing else and resembles an "S"

3️⃣ The current alternative looks like Kebab