by the photo you posted it seems to be stuck at the PCIe Latch. Either the latch broke and not releasing or you need to try in install the GPU card until the gray latch pops up in the secure position and then push down on the gray latch again and see if it will release the GPU card.
Trying gently playing with the Gray latch and see if it will release the GPU Card.
very carefully see if you can pull the GPU card away from the latch. If you meet any resistance stop.
This Tech site thread a User has the same issue you now have with a stuck GPU card: https://linustechtips.com/topic/1028222-gpu-stuck-in-the-pci-e-slot/
The above link give some tips on how to unstick the GPU card from the PCIe slot.
From a Tom's Hardware Thread concerning the same problem: https://forums.tomshardware.com/threads/gpu-stuck-in-motherboard.3570909/
first push the GPU in as if installing until its in and the pcie retention tab pops up. NOW for the removal, if the GPU was installed correctly the TAB should be in the UP position AWAY from the MB. PUSH the tab down until it stops about a 45 degree angle it will sort of push on the GPU forcing it out. dont be afraid just slowly wiggle the GPU out of the PCIE slot and it will come out