It doesn’t sound like you’re getting enough fruits and veggies. The fiber in vegetables especially helps slow down food passing through the gut and gives your body time to absorb nutrients. Even something as simple as serving your beef stroganoff over zucchini noodles would be helpful to increase your veggie intake. And/or add spinach to the broth to get some leafy greens. I don’t know the ins and outs of keto, but I’m a huge fan of the “eat the rainbow” mentality to ensure I’m getting enough fruits and vegetables. Are there ways you can make your meals less… brown?
Also, if you’re drinking anything other than black coffee/tea, you’re breaking your fast. If you find coffee too bitter, try a pinch of salt or baking soda, or try cold brew as the cold water doesn’t cause coffee beans/tea leaves to release as many bitter compounds. I don’t drink coffee as it makes me jittery (and use tea for an afternoon pick-me-up as more of an exercise in mindfulness than for caffeine) but instead drink a ton of water; being properly hydrated helps keep me awake because I can’t work at my desk all day without moving. I have to keep getting up to go pee!
When in the day are you starting your feeding window in relation to when you sleep? It may be worth shifting things so you’re not eating too close to when you sleep and ensuring that you get a full night of rest. I find it’s way easier to wake up in the morning if I start fasting a few hours before I go to bed and drink water as soon as I get up.