https://wccftech.com/macos-10-15-6-fixes-usb-connectivity-issues-with-2020-macbook-air-and-macbook-pro/

With the release of macOS 10.15.6, Apple has fixed the annoying issue with USB 2.0 accessories and 2020 MacBook Air and MacBook Pro models, which would cause frequent disconnections.

The issue impacted the usage of USB-C hubs and devices connected to it. The devices would connect at much slower speeds than normal. Some of them were working at 12 Mb/sec instead of 480 MB/sec. The workaround for the issue was to use a powered USB hub, which would fix the connectivity for most users, as per device maker Elgato: