Progressively slow after returning from the Nether (MC 1.16.102.0)

My game is progressively slow after returning from the nether (1.16.1). The frame rate drops quickly, keeping the game extremely slow. I reduced all video settings that could affect performance and did not solve the problem. It is the first time that this has happened. High CPU usage is detected.

My computer: Ryzen 7 2700X, RTX 2070, 8GB RAM, 1TB SSD NVMe. Windows 10 Pro. NVIDIA GeForce Experience is installed.