12 month old cries every wake

My baby has always been ok with the cot, and up to about a month ago was sleeping ok with only 1 or 2 wakes. We're now up to 3 or 4, despite moving to 1 nap, reducing day sleep etc etc.

He has gone from being able to roll over and go to sleep (granted, we would let him get extremely tired before bed) to needing to fall asleep in arms but waking and standing and crying as soon as we try to put him in the cot. Once hes 95% asleep in arms you can transfer him. He is not fed to sleep.

He will also wake from daytime naps, sit up and look around then stand and start crying, never lies there babbling like I hear of other babies doing (and he used to on occasion).

Im also aware each and every sleep training/aid resource is going to tell me to leave him to cry. Ive tried 10 minutes with me singing in the room, shush patting and unless he is exhausted enough, he escalates. I wont leave him to cry.

Do I just need to push him to the point of exhaustion every night? Is there something i can do to make him hate being in his cot less? As i said, not that long ago we were getting 7-9 hour stretches, and i dont know what's changed.

Prior to 1 nap transition he was having nearly a 7 hour final wake window and 9-10pm bedtime.

Now on 1 nap he is more like

Wake 7am

Nap 12-1:30

Bed 8:30-9

Im back to work in a month and worried about how I'll cope.