Putty silicone or the “Christmas tree” style ear plugs never work for me to completely prevent getting water in my ears, so I’d be interested in hearing about any other ear plug type recommendations. To answer your question OP though I like these caps that cover my ears, and they prevent water for a bit but never completely. I’ve thought about trying these little “ear shower caps” under a cap like you link above - it may not prevent water 100% but could possibly make a treacherous path and make it hard for water to get there during a swim: https://www.amazon.com/dp/B09HBYB1JM/ref=cm_sw_r_cp_api_i_5NNASB36XNJJNC7Y4HHZ?_encoding=UTF8&psc=1