Stock assets are fine, looking like another game is not a problem

Never be shy about using stock assets. Even if your game looks like other games, there are 40m players on Steam at any given moment. The chance that all of those players have seen a given asset is almost zero. Once the game is good there is nothing wrong with looking like other games, in some cases it is even a plus.

Look at Supermarket Chaos, exactly the same assets as Supermarket Simulator. Or MotorTown, which runs entirely on Synty assets. Do not burn the budget you have on artists in the name of being original. Especially on your first games. Once you have had some success, good artists are usually a multiplier on the games that follow.