Help! My Internet is Stuttering and I Can’t Figure Out Why

I've been experiencing major internet speed issues. My connection is slow, with frequent spikes that make everything laggy. I've tried different networks, including Wi-Fi and USB tethering from my mobile data, but the problem persists. I'm using LatencyMon to investigate, and I've noticed that the ndis.sys process has really high DPC latency—sometimes over 1000—when I'm on Wi-Fi. When I switch to USB tethering, the wdf01000.sys process exhibits similar issues. Here's a list of everything I've tried to fix it: Doing a DDU clean install of drivers, updating the BIOS, resetting the Windows networking stack, running in Safe Mode with Networking (the problem still happens), disabling EXPO, turning off power-saving settings on network devices and USB ports, updating chipsets, running CMD commands (sfc/scannow, DISM, etc.), uninstalling drivers for Wi-Fi, Ethernet, Bluetooth, disconnecting every USB device, making adjustments to processor settings, and un-parking the CPU. Unfortunately, nothing has worked, and I can't even watch YouTube without lag or play online games without getting 1000+ ping. This all started out of nowhere just a few days ago, so if anyone has a solution, I'd really appreciate the help!