Update from my side -
It now renders normally, I no longer see black skinny lines in sky and black outlines around clouds and chunks.
I did nothing from my side, it got fixed by itself.
Maybe updates from other software like Steam, or Windows update got it fixed.
My laptop specs -
CPU - AMD Ryzen 5 4600H
GPU - NVIDIA GeForce GTX 1660 Ti (GPU #0)
AMD Radeon Vega (GPU #1)
Directx version - DirectX 12
Having same issue in my new laptop.(minecraft version 1.16.210)
(In my old desktop this doesn't happen.)
Update 2 -
Earlier I said the bug got fixed for me but I was wrong. The bug is still there.
The bug is inconsistent on my device, sometimes everything renders in normal way, but after launching the game next time the bug appears again.