I also like the lightning bolt. But it's all up for grabs. Square terminals use ₿. Here in Nostr, Chachi, Chorus and a few others use a slanty ₿. Many Nostr apps use just letters, but half use SATS for the plural and half use SAT also for the plural. Coinbase, Kraken at friends tend to use the hamburger. Ditto seems to use the hamburger, the word Sats and the lightning bolt all at the same time. Binance uses the S-dollar-sign thing. On and on.

So at least 5 genuine contenders, and even two is one too many. It's hard to argue it's not an issue, or that any one is in the lead.