I had used both wood and lego type blocks for my jack pads over the years. I had no real problem with either until last year parked on grass.
I was using the yellow leveling/jack pads to give a larger foot print for the jacks. Well it rained and the soil started to give way to not only mine but a lot of other rigs. The yellow pads just did not provide enough of a foot print or strength (three broke) to do the job.
So got home did some research and ended up with these:
https://www.outriggerpads.com/for-rvs/
Am really happy with them.