They do plenty of terraforming adjacent tasks in TNG, mainly for planets that have recently joined the federation, or are undergoing some kind of collapse prevention. I think the issue with Project Genesis and similar is that they were “bombs” that would instantly overwrite the ecological system on a planet with a predetermined one, wiping out the existing ecological system in the process, to put plainly, killing everything.

The terraforming I’m talking about is stuff like earthquake mitigation, adjusting “atmospheric conditions” to stop greenhouse effects or similar, etc. And it’s all signed off in triplicate from the federation etc, not just lobbing a terraforming bomb at a planet on a whim.