forex.pm forex forum binary options trade - Get the longest chain by keeping a constant low difficulty

I'm struggling with this question that should be easy to answer.

If the truth is the longest chain,
What if I redo all the work from Block 1
until I have the longest chain by keeping a constant low difficulty.
Then I could produce tons of blocks and just modifying the timestamps to keep a constant difficulty. I should be able to generate a longer chain than the actual height.

I am aware that I am missing an important point.
What protections are in place against this process? Or my math is broken ?

I hope I have expressed my thoughts well
Thank you in advance for your answers