Unexpected Input Lag, Game Crashes, and Performance Drops on PC (Ethernet)

The game has changed for me; it's become sluggish and freezes, and the lag worsens with increased ping, even if the ping fluctuates between 30 and 60. Sometimes, when I launch the game, it crashes on its own. Occasionally, when I enter a match, the screen freezes black and won't clear until I restart the game.

I'm playing on a strong PC build (RTX 4060 Ti / i5-12400F) over a wired Ethernet connection, and I've already lowered the settings with no resolution. This issue started suddenly two days ago.