Host Connection Issue

I have high-speed fiber internet. My regular connection and download speed are fine. However, for the past week—especially during the evening hours (GMT+3)—I’ve been having issues connecting to games (after accepting a match), and I end up getting penalized. Sometimes, even when everything seems normal and my ping is around 50–60ms, I suddenly experience a ping spike (1200–2000ms) mid-game, causing severe lag and making the game unplayable. This issue only started happening this week; I had no such problems before. I’ve tried connecting through 3 different regions (EU east-west-russia) and tried known troubleshooting methods, but nothing has worked. Is anyone else experiencing similar issues?