game running terribly

[Steve]

reloaded a save, game threw my cars in breaking them and now the game is running at 10 frames, also the game runs very badly when zombies spawn in,
post edited, i tabbed back into the game and it was frozen with this, :Fatal error: [File:D:\UnrealEngine-5.2.1-release\Engine\Source\Runtime\RenderCore\Private\RenderingThread.cpp] [Line: 1274]
GameThread timed out waiting for RenderThread after 120.00 secs


0x00007ff687eb3d6b DriveBeyondHorizons-Win64-Shipping.exe!FRDGBuilder::ForceCopyCrossGPU() []
0x00007ff687ebe110 DriveBeyondHorizons-Win64-Shipping.exe!FRenderCommandFence::Wait() []
0x00007ff684f91714 DriveBeyondHorizons-Win64-Shipping.exe!FEngineLoop::Tick() []
0x00007ff684f9c43c DriveBeyondHorizons-Win64-Shipping.exe!GuardedMain() []
0x00007ff684f9c4ba DriveBeyondHorizons-Win64-Shipping.exe!GuardedMainWrapper() []
0x00007ff684f9d37c DriveBeyondHorizons-Win64-Shipping.exe!LaunchWindowsStartup() []
0x00007ff684fa77d4 DriveBeyondHorizons-Win64-Shipping.exe!WinMain() []
0x00007ff689c8cd02 DriveBeyondHorizons-Win64-Shipping.exe!__scrt_common_main_seh() [D:\a\_work\1\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl:288]
0x00007ffeb2a3e8d7 KERNEL32.DLL!UnknownFunction []
0x00007ffeb2dbbf6c ntdll.dll!UnknownFunction []