It's hard. I am enmeshed in modernity fairly thoroughly but I am trying to do better. I have an EV heat pump and all electric house, I try to find others that are also aware of how bad things are likely to get in future, I am doing National Tree Day every year and also growing veges and fruits and herbs at home, and I am trying to limit exposure to and use of plastics (but that is so damn hard unless plastics become illegal...)
Being aware and using that awareness to try and change behaviour is a big focus. But also, don't be too hard on yourself. We were born into this mess too, we didn't create it in one generation, and it is likely to be a slower decline from a human perspective rather than instantaneous, though on geological scale it's basically a blink of an eye. I was super scared of global warming and nuclear war as a kid, and while risks of both have increased I'm still alive and even with a choice to reduce use of certain things, I think I still have a great life, and my daughter has so far too.