I've been using these LPS Liquid Protein Supplement packets that I first had in the hospital post-op.
They're 1oz of a slightly thick syrupy liquid. They're all sickly sweet, artificial grape and watermelon flavor are the two I've had.
I wasn't able to keep doing the shakes, just hated the taste/texture, and these were far easier for me to get down. Just one ounce and it's over with.
https://store.bariatricpal.com/products/lps-sugar-freer-collagen-whey-liquid-protein-supplement-nutritional-designs-oz-packets-1