Ah OP I feel your pain and sadness. Life is hard and the relentless downward spiral the world seems to be taking right now is frightening. I worry for my kids too. And sometimes it seems beyond hard and futile just to keep trucking on.
But it is worth trying to see the good; we are all here; we're alive! And, and I genuinely mean this as something positive, it is always possible to die. This is true for you and for your kids - there is always an exit door and we can walk through it any time we like really. So why not wait and see? Wait for the weather to turn, to step out of the door and smell the sap rising in the trees and the sun warming the paving slabs and feel the life inside you answering that? To talk with that friend who always makes you feel so seen and understood, who always leaves you laughing no matter how serious the things that you've both shared? To share a joke with your kids that randomly escalates until you're all crying with laughter and can't stop? To start reading a book which totally sucks you in and takes your thoughts in a direction that they've never gone before? To see your kids fall in love and get married, or achieve something they're proud of? To hold your grandchild? If and when the darkness closes in again, the exit door is still there waiting. But if you wait there will be moments worth experiencing.
So much for the sales pitch. You don't mention being suicidal really, just darkly cynical about life and your former 'naivety' for thinking it was worthwhile. So can I ask - what used to give you pleasure? What makes you unhappy now? What do you fear for your children's futures that you wish you could spare them? Can any of this information be used to form a plan that can improve the outlook, or even just your day to day quality of life?
Also, and I hate to be so tedious, but we are machines of flesh and blood and chemicals, and our brains and our feelings are only functions of these things: so are you getting enough sleep, enough exercise, enough water, eating well, getting hugs? Feeling miserable and hopeless can make all these things harder to do (not to mention small kids can make sleep next to impossible to get), but ironically, if you can do them, you can't help but feel better, and if you can't you absolutely will feel worse - it's just the machine doing what it does. I mean even if your perspective on the world now is 100% right and realistic - and who am I to say it isn't? - do you want to just FEEL better, day to day, even if it's just a trick? Do you want to inculcate your kids with healthy habits that will make them better able to endure what life throws at them? Sleep, fluids, sunshine, nutritious food and oxytocin - these are the hacks that can make you feel happier even if there is genuinely nothing to be happy about.
Philosophically, it's a valid position that life is suffering, and you're not wrong necessarily about that. But practically, if you plan to go on, you might as well make it as pleasant as possible for yourself.