In Beta 11, the developers introduced "DirectX 12 Ultimate" as the default renderer. On older GPUs (GTX 1000 series or older), this causes a black screen 10 seconds after login.
Beta 11 includes a new rendering pipeline that may default to suboptimal settings for mid-range PCs. To regain your performance: tuff client beta 11 fix
Are you running any or texture packs alongside the client? In Beta 11, the developers introduced "DirectX 12
New fixes and features are being added regularly. Keep an eye on the GitHub releases page for newer builds, and consider updating both your client and TuffX plugin to the latest versions when they become available. In Beta 11
: Addressing crashes when connecting to 1.21.x servers using the integrated ViaVersion implementation .