It´s free and the website of Meterplugs Loudness Penalty Plugin
after analysing and adjusting to suggested settings a reupload of that file to streaming services turned out to be the perceived same loudness but better dynamics so i guess this is working well..
i recommend to check out this dude. doing video’s about music production, mixing and mastering @ his channel. his videos has more a kind of controversial aproach but he always brings something to the table.. good guy..
Another metering (not free) i can really recommend…