Issue with FlashLoanArbitrage + Use FakeDex to simulate (able to deploy FakeDex, but unable to execute functions)

[Glow-in-the-dark]

This is my code repo:
https://github.com/Glow-in-the-dark/Solidity_Flashloan_Hardhat

I am able to deploy on Sepolia Testnet, with:

• ( Dex.sol, address below)

FakeDex Contract deployed: 0xB8De86Fce1BDE6e3D33CEb00C4e3F0c7D5C6752d

I am trying to deposit DAI, so that after deposit, i can then run the buyDAI() function, to buy DAI at a discount.
However, when i tried to call the depositDAI() and depositUSDC() functions

the seems like nothing happen. it just keep saying pending. (Not sure what's the issue)