Parenting consultation!! Need expert help!! Sleep issues in infants

We used to sleep together on the floor until about 10 months old, but in winter it seems cold, so we brought in a baby crib to put the baby to sleep separately.
It seemed like I was sleeping well for a month or two, but now that he's just passed the milestone, he refuses to stay in bed~

When I try to put him on the bed because he's sleepy, he starts crying loudly and insists on getting down.

As it worsens gradually, I now dislike even going into the bedroom, and when it gets to bedtime...

I closed the door and played on the floor while waiting to get sleepy, but even then, it kept knocking on the door, asking to be let out. ㅡㅡ;;

Maybe they refuse to sleep alone because they dislike it, or perhaps they're refusing sleep itself, and I wonder if it's bad for their emotional well-being.
My heart hurts so much when I cry myself to sleep.

I thought I might as well try, so I started putting him to sleep alone for two days, and when he wakes up crying in the early morning, he comes to our bed to sleep, and he definitely sleeps well~
Please advise me on what is the right thing to do.