Astronomers Detect a Possible Signature of Life on a Distant Planet

If life evolves on a planet with only oceans, no surface, imagine how much longer it would take to discover rockets that can leave the planet.

Like if there was no surface on earth, and only fish, there must be some very significant reason for advanced fish to even want to leave the water, let alone the atmosphere

That seems like a very landbased mindset. From a high level, what is an ocean but a thick atmosphere? I could even imagine an underwater culture would be quicker to explore because they would surely discover the surface of the ocean quicker than we discovered the concept of the atmosphere and that innately leads to the questions of whether the atmosphere has a "surface" and what is above it.

There is also the issue that they will likely never discover fire and thus chemistry and metallurgy.

Chemistry and reactions would absolutely still be a thing. Reactions happen underwater all the time such as the complex decay of organic matter.

The fire meta get's postponed until trapping air inside bags happens (could be seaweed/skin based bags).

Then you need to make a habit of collecting a bunch of air and trapping it and then can begin exploring chemical reactions in the air.

ex: take dead but not decomposed organic matter, dry it out in hot air bag (maybe cover the bag in black squid ink and float the bag of air in the ocean out in the sun's rays for day to warm it up.

Then eventually you need to have the insight to do friction based experiments in the bag with dried materials and then one discovers fire in a massive breakthrough not dissimilar to when humans created Bose Einstein Condensates for the first time in highly specialized environments.

Nothing here says "impossible" to me. I bet if whales had fingers to easily manipulate matter they might've already done all this by now.

While I agree that there is no logical reason that underwater organisms could not become highly intelligent or advance to the level of doing experiments with fire, it is clear that being underwater is an additional barrier.

As such, the number of intelligent underwater civilizations, that could get near our present level of advancement, would likely be significantly lower. Not impossible (because of how large the universe is), but some order of magnitude, less possible.