not a valid identifier while exporting path

I have two Cuda installations namely 11.8 and 12, and would like to switch between them without manually editing the .bashrc file and sourcing it again.

For that I have come up with the following function placed inside .bashrc

export CUDA_11=/usr/local/cuda-11.8/
export CUDA_12=/usr/local/cuda-12.0/


#Default Cuda12.0 will be loaded, use this to unload 12 and load 11.8

function switchCuda { 
 local pathToUnset=$1"bin/"
 echo $pathToUnset
 local lib64ToUnset=$1"lib64/"
 local pathToSet=$2"bin/"
 local ldPathToSet=$2"lib64/"
 local currentPath=:$PATH:
 unset PATH
 local removedPath=${currentPath/:$pathToUnset:/:}
 removedPath=${removedPath%:}
 removedPath=${removedPath#:}
 PATH=$removedPath
 export $PATH

 currentPath=:$LD_LIBRARY_PATH:
 unset LD_LIBRARY_PATH
 local modifiedLDPath=${currentPath/:$lib64ToUnset:/:}
 modifiedLDPath=${modifiedLDPath%:}
 $modifiedLDPath=${modifiedLDPath#:}

 LD_LIBRARY_PATH=$modifiedLDPath
 export $LD_LIBRARY_PATH
 #echo "I AM DONE UNSETTING THE PATH" 
 if [$2 == "" ]; then
     echo "Simply unsetting cuda path, as provided cuda path is empty. use loadCuda to load the desired path"; return;
fi
    
 export PATH=$PATH:$2
 export PATH=$PATH:$pathToSet
 export LD_LIBRARY_PATH=$ldPathToSet${LD_LIBRARY_PATH:+:${LD_LIBRARY_PATH}}
 }

export -f switchCuda

function loadCuda { 
 export PATH=$PATH:$1
 export PATH=$PATH:$1bin
 export LD_LIBRARY_PATH=$1lib64${LD_LIBRARY_PATH:+:${LD_LIBRARY_PATH}}
 }

export -f loadCuda

The intended result of the above function should be as follows -

#in a fresh terminal
nvcc --version (should result in 12, as by default cuda 12 is added to path)

switchCuda ${CUDA_12} ${CUDA_11}

nvcc --version (should be 11.8, as cuda 11.8 will now be in path, nobody should be able to find 12)

However, when I call this function from the command line, I get the first error is as follows -

bash: export: `/opt/ros/noetic/bin:/home/atharva/ros_catkin_pkg/install_isolated/bin:/opt/intel/oneapi/vtune/2022.2.0/bin64:/opt/intel/oneapi/vpl/2022.1.0/bin:/opt/intel/oneapi/mpi/2021.6.0//libfabric/bin:/opt/intel/oneapi/mpi/2021.6.0//bin:/opt/intel/oneapi/mkl/2022.1.0/bin/intel64:/opt/intel/oneapi/itac/2021.6.0/bin:/opt/intel/oneapi/intelpython/latest/bin:/opt/intel/oneapi/intelpython/latest/condabin:/opt/intel/oneapi/inspector/2022.1.0/bin64:/opt/intel/oneapi/dpcpp-ct/2022.1.0/bin:/opt/intel/oneapi/dev-

utilities/2021.6.0/bin:/opt/intel/oneapi/debugger/2021.6.0/gdb/intel64/bin:/opt/intel/oneapi/compiler/2022.1.0/linux/lib/oclfpga/bin:/opt/intel/oneapi/compiler/2022.1.0/linux/bin/intel64:/opt/intel/oneapi/compiler/2022.1.0/linux/bin:/opt/intel/oneapi/clck/2021.6.0/bin/intel64:/opt/intel/oneapi/advisor/2022.1.0/bin64:/home/atharva/.local/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin:/snap/bin:

/usr/local/cuda-12.0:/usr/local/cuda-12.0/bin:/home/atharva/TensorRT/TensorRT/bin/:/usr/local/cuda-12.0/:/usr/local/cuda-12.0/bin:/home/atharva/TensorRT/TensorRT/bin/:/usr/local/cuda-12.0/:/usr/local/cuda-12.0/bin:/home/atharva/TensorRT/TensorRT/bin/:/usr/local/cuda-12.0/:/usr/local/cuda-12.0/:/usr/local/cuda-12.0/bin:/home/atharva/TensorRT/TensorRT/bin/:/usr/local/cuda-12.0/:/usr/local/cuda-12.0/bin:/home/atharva/TensorRT/TensorRT/bin/:/usr/local/cuda-12.0/:/usr/local/cuda-12.0/bin:/home/atharva/TensorRT/TensorRT/bin/:/usr/local/cuda-11.8/:/usr/local/cuda-11.8/+bin/:/usr/local/cuda-12.0/:/usr/local/cuda-12.0/bin:/home/atharva/TensorRT/TensorRT/bin/': **not a valid identifier**

The last line of the above error message is as follows -

12.0/bin:/home/atharva/TensorRT/TensorRT/bin/': **not a valid identifier**

I believe there are multiple issues -

1. String substitution is not happening correctly
2. cuda_12 is still coming in path, even after removing it.
3. Also, there is another issue, Assume I run switchCuda {CUDA_12} "". It should completely remove cuda, and doing something like nvcc --version should result in command not found. However, it is still able to find nvcc. Why so ? How can I achieve my intended result?

TIA