@thull , I am SO sorry to hear what you're dealing with! Please know that my thoughts will be with you for your upcoming surgery. It must be so frustrating.
I know that for the most part you're on clear liquids right now, but I've been meaning to post a recipe for my go-to homemade super-healthy smoothie, etc. It takes like 5 minutes to throw together, but it has a lot of protein and other nutrients, and it's delicious (it can be tweaked according to people's tastes), and it's cheaper than a lot of the pre-made stuff. It also contains a good amount of calories to help you put on weight (when you're able to drink them).
Another thing I often drink for breakfast is also easy and healthy, and has no fiber to cause issues. It's my own version of Indian lassi. I don't know if your doctor will give you the OK for it yet, but for when you (and others here) can try it:

1/2 cup Greek yogurt (with active cultures--I use Chobani)--I use plain, non-fat (easier to digest), but vanilla would be sweeter and also taste good

1/2 cup coconut, soy, or almond milk--I use the sweetened vanilla kind...cow's milk might be fine, but might be a little harder to digest

A few drops of vanilla

Spices (I use cardamom and turmeric, but nutmeg or cinnamon would be good too) and, if you want it sweeter, honey to taste

2-3 ice cubes

Throw it all in a blender and drink! It goes down easily, but it's a healthy start to the day (with a giant cup of coffee, of course! 🙂 ).

I'll post the other recipe at some point as well, if anyone is interested.

Again, best of luck and warm wishes to you, @thull !

P.S. Happy New Year to everyone!