It sounds silly but also a lack of ability to make fire puts a dampener on things. No easily digestible cooked food. No ability to make metals.

Perhaps somewhere near an underwater volcano there is a technologically advanced octopus city waiting to be found?

Like Octlantis, but hotter, and with steel (“Cuttlefisheffield“?):

https://www.theguardian.com/environment/shortcuts/2017/sep/1...