It's true, both have a 30 metre hose. I tried to do some research and found two differences.
two differences: the 20 was launched 1 year earlier than the 33 and the price of the newer one is significantly more expensive than the 20. I don't know which one I bought in 2023. The prices are no longer comparable. I would buy the cheaper one today, the 20.

Ours is 35 metres long