One of my favourite Stronghold BLs is "Choco Milk Shake" (2022, Youtube). Aside from its overall high story, production and acting quality, I have a soft spot for dog/cat transformation stories. I'm a dog person (I love my real life dog to pieces!), but I'm also good with cats. The second episode (short story) of "Close Friend" (2021, Viki) - starring First and Ja in which First Chalongrat (who I adore!) delivers a superb acting performance as a shapeshifted cat - is another one that I really love, even though the quality of the rest of this series (collection of six separate short stories) is mixed.
Anyways, I just finished watching two more such BLs, both of them cat-becomes-cute-boyfriend: "Meow Ears Up" (2022, Viki) and "Beside You" (newly released on Youtube). Despite the considerable weaknesses of each, I rather liked both for two simple reasons: I can relate to the cat-becomes-cute-boyfriend concept, and I found the respective cat-becomes-boy protagonists/actors really cute and sweet.
While "Meow Ears Up" is a mediocre but normal Thai series, "Beside You" (three-part mini-series) is basically 40 minutes of product placement (advertising) with a bit of ultra-lightweight BL storyline and attractive but inexperienced actors to draw viewers. That doesn't really sound like much of a recommendation for either, does it? Well, I'm recommending these two series only very conditionally: If you especially like cat-becomes-cute-boyfriend and if you think the respective cat/boy protagonists are cute ("Meow" in the first, "Hope" in the second), you may enjoy these BLs, despite their considerable flaws.