No. I am somewhat opposed to all daylength patches, they will never work, and they fragment the game whilst introducing unwanted problems.
You could fork FIRS and modify production values https://github.com/andythenorth/firs
The majority of industries use one of 5 templates ("templates/industry_*.pynml"). These contain 'produce' blocks, and changing the base production would be a matter of inserting a multiplier there. This may not cover all industries, and may cause broken calculations, constants or strings elsewhere, but it's possibly close enough.
For a specific map size, OpenTTD targets maintaining a specific count of industries on the map. So no, the map shouldn't get full of industries, new industries will be rarely built unless another industry has closed- I see new industries being created during the game. But I disabled closing of secondary industries. Does that mean that the number of industries will increase until I have no more free blocks on the map?