I got the same error today. In previous version of tf, I need to install a Nvidia toolkit to get the file.
Here is the right toolkit for the cudart64_110.dll file: https://developer.nvidia.com/cuda-11.3.0-download-archive
Then just follow the installation guide. If you need more help or it doesnt work, just write it.
solved tensorflow: Could not load dynamic library ‘cudart64_110.dll’; dlerror: cudart64_110.dll not found