I think Arcanine is most based off of Shisha (from the Ryukyuan culture of China). Shisha appeared as a cross between lions and dogs and were used as protection against evil spirits. Indeed, in the original Yellow Pokédex entry it says that Arcanine is considered a legendary Pokémon in China.
There is a Chinese legend that says a king had a Shisha in his necklace and visited a town that was being continuously destroyed by a sea dragon who curiously shares similarities with Gyarados. The king was beseeched to protect the town and held up his necklace before him. A deafening roar shook the earth and a giant rock appeared from heaven, crushing the dragon.
In the Yellow Pokédex, Gyarados is known to have “totally destroy[ed] cities in ancient times”.
So I believe that Arcanine was most based off of the Shisha and this particular legend in Chinese mythos.
The link I provided also mentions that some of Arcanine’s other inspirations were the Komainu (the guardian statues of Chinese shrines), the Xiezhi and Haetae, which are of Chinese and Korean origin, respectively.
Hope you’re having a good day!
Feedback is appreciated.
Source: https://aminoapps.com/c/pokemon/page/item/arcanine-origins-and-inspirations/0ehZ_IrpPXx2VYNMz8VoeklQlxWN5