Not one or the other of these ventures have a substantial use-case. They are meme-coins. Theoretical betting at best. I’d be lying on the off chance that I said I never possessed any. But fair a number of dollars here or there. These aren’t genuine ventures for genuine investors. And they likely won’t be around within the next 10 year.
Dogecoin is one of the oldest coins and it is still around and will continue to exists. I can't say same thing about Shiba Inu Coin. If you need to choose between the two, i will choose Doge coin on the reason that it is being promoted by Elon Musk an he is seriously working behind the scenes to make it a better crypto currency.