At a loss with 7 month old. I need different perspectives

In the last two to three weeks baby refuses to sleep in his cot at all. The minute we put him down he will start fussing and waking up and then crying until he gets picked up. It doesn’t matter how deeply he sleeps. We’ve even tried a heating pad which worked before but not anymore. So we’ve had to do 7 sleep cosleeping because we’ve tried everything. Neither of us are willing to to cio. Putting him down drowsy but awake also doesn’t work. Neither does trying to pat him to sleep

And now it’s spilling into daycare where he won’t sleep in the cot.

Not sure if it’s because he has eczema that he’s sleeping is bad or whether he is going through separation anxiety or another sleep regression 😩.

Not really sure if there are options left.