I really struggle with your logic tbh.
We had 2 wickets to get in the last minutes on the final day in the first test.
Not declaring would undoubtedly of decreased our chances of winning and declaring increased our chances on winning the game, surely that can’t be disputed??
The fact the game went right to the end of the final day, meant not declaring would having taken more time out of the game and would have only given us a chance of draw.
It was a calculated risk that could have went either way we needed 2 wickets and they had 55 to get.
We went into this series needing to win back the ashes back and had won the toss drawing should have not been our priority winning should have been.
It went to the end because we simply couldn't bowl their tail out. As already stated also.