Close but not exactly, your body is capable of freely switching between fat or carb burning. When your body really thinks it's starving, it will start "eating" your muscles instead.
Fat burning gives steady supply of energy instead of the highs and lows of energy dense carbs. You feel this the hardest after lunch, on carbs you'll often feel tired and sluggish. You don't have this on keto.
Switching into keto can be a miserable experience though, so you're right about that. Once in keto it's chill.
The things I currently selfhost are:
Always searching for other interesting and useful things to selfhost 😅 For Matrix I'm currently using the Element client, what is your experience with Cinny? Would you recommend it?