Ask HN: Why marketplace health insurance is much more expensive now than COBRA?

I left my previous employer 1.5 year ago, and had to pay myself for the COBRA provided health insurance. It was pretty expensive as it seemed to me at that time - around $1550 per month for a family of 6 (my wife and I around 40 y.o. and 4 young kids). I remember looking up marketplace insurances at that time at coveredca.com and there were similar deals for cheaper or similar monthly premium.

Now, 1.5 years later, I'm still self-employed and like everything about it, but COBRA period is over and I'm quite surprised to see that marketplace insurances are much worse than they were when checked last. Any insurance with comparable conditions starts anywhere at 2.1-2.5K a month, and that with much larger deductible and out-of-pocket limits (f.e. - on COBRA I had 4.2K out-of-pocket for the whole family, while those deals are all at 14K out-of-pocket limit).

Can someone please explain to me what has happened in 1.5 years? Is this the effect of the "Obamacare" repeal?

And does anybody know of any software devs/engineers professional unions that may provide group plans for self-employed devs?

Any other suggestions what to do?

I'm mentally preparing myself to cash out 2.1k a month for the silver level PPO otherwise (I'm not eligible for the tax credit).

Thank you!