I have tried to follow along your tutorial on this stream from part 1. But, when it comes to applying bump node as you explained in this part 2 for the leaf, the eevee view port becomes extremely slow and unresponsive. The problem goes away when I disconnect bump node. How does that happen? I’m using blender 2.81a on mac.
I'm not sure about that. Something very fundamental in Eevee changed greatly between 2.8 and 2.81. I have several scenes which work flawlessly on 2.8 in Eevee render, and in Look Dev on both Cycles and Eevee, but on v2.81 the viewport grinds to a halt in Eevee render and Material Preview on both Cycles and Eevee.
This is on a Ryzen 5 1600x with a GTX 1660Ti.
I haven't been able to understand why this is happening so I cannot offer a fix. In fact, I have had to resort to doing all my work on 2.8 and only opening 2.81 when it's time to render to take advantage of the new denoising.