After placing a large number of devices in the game, I found that the client became extremely sluggish. After inspection, I found that the CPU was heavily used for real-time rendering of the devices, without being handed over to the GPU for rendering. A single core occupied 100%, while the other cores were not assigned computing tasks, and the GPU remained low occupied!
Configuration: CPU: i7 14650 GPU: rtx 4060

Is this a common problem with OpenGL or is there an error in the rendering settings of MOD?

Minecraft an a single-threaded game.
One thread for render, and another one for "logic" (for example - mobs AI, logic for machines, turrets, furnaces and etc).
So yes, the processor will almost always be the bottleneck.
Also, yes, the game and the mod have some problems with rendering and optimizing logical calculations.
All versions of minecraft has the same problem.

AND make sure game runs on P-cores of your processor. They have more performance than E-cores.