I wish you would do more stuff like this. Love the DIY content. Not a fan of the negative news reviews you've been doing. Much prefer the light harted fun videos.
Reckon that Plastic trims are by their nature made from Petrochemicals and degrade in the UV a bit like that supposed Glass in your Car headlights going Milky, as they degrade, obviously over time the more it does its job as you repeat this operation more it takes in until it's semi saturated, so by then it could hold up for a serious amount of time... I used to use Baby Oil on the bumpers and on the dash and on hard plastic components on the seat moulding that had become tired... Great Review....
Another excellent cleaning product is white diamond metal polish, Best metal polish I've ever bought seems expensive but a little goes a long way A lot of truckers use it for their chrome wheels/exhaust stacks etc. Not tried it myself yet but cherry blossom liquid shoe polish works well on black trim, Plenty of vids on RU-vid.
This stuff is very good, and it lasts, over six months and no signs of fading yet. Top Tip Black plastic absorbs heat, if the weather is even slightly sunny, be careful. DO NOT leave this for the recommended 10 to 20 minutes before wiping off, maybe a minute, but in warm weather it goes tacky VERY quickly. Paint on, wait for a minute, wipe off. Otherwise you'll regret it. But it is a great prosuct, and it seems to keep working and getting darker over a day or so after application. The trim on my car was jet black today, much darker than it was yeaterday. Dont get it on anything that isnt plastic! I tried some on a cotton bud to see what it would to some scuffs on my door card. I can confirm that if you carefully paint only the scuffed area, it takes about 95% of the marks away.
