I always thought these are individual, I still think so 
I never got euphoria (well I felt great on day #6 or something but thatās it, never again and it wasnāt extreme), high energy, I have no idea what is the mental clarity people talk about⦠And I didnāt lose fat because I still get hungry and eat a lotā¦
I got fat adaptation and lost my water weight changes.
Carnivore or close to it is special in my case, my attitude to food definitely changes but no euphoria, high energy etc.
In my first on/off keto years I ate 40g net carbs on keto, now itās 5-20g.
I am out of ketosis at 50g net, at least that was the case last time I tried to figure it out. Itās hard as I feel about the same in and out of ketosis, there are subtle signs under certain circumstances but they are not fully reliable. Weight changes helped in the first years but not anymore. But as I donāt get benefits just being in ketosis, only if I drop my carbs, I donāt care, I go lower.
It doesnāt seem sweeteners matter in my case (unless I go too high with my net carbs I presume but I donāt eat that much sweetener). I used to eat sweets every day on keto, I obviously donāt do it when I do carnivore (or super close to it) but I experimented with very low net carbs with sweeteners lately, nothing seemed to change.
But itās me, others have problems with them. Or with some of them.
My energy do seem to be a bit better if I keep my carbs very low (itās not all about one number though, 20g is suberb if it comes from eggs and liver and total carbs never seemed to matter to me, only the net) but eu[phoria? I donāt even believe thatās a thing, itās so strange and why would want that from my woe? Though itās always nice to feel great for a hedonist⦠But there are so many other ways
I get it from sunshine and itās interesting that my energy dropped when I lacked sunshine but this stopped on extremely low net carbs⦠So strictness has something to do with my energyā¦
I donāt think protein is a problem. Everything I have read in the last years, experiences of me and others shows this - but some people are able to overeat protein. We all have a higher limit to protein, no wonder, we have a fatal amount of water intake too, most of us just never reach it even if we eat protein galore. I never had problems with my unnecessarily high protein intake - and I canāt comfortably eat less protein so itās easy to decide what to do. I canāt measure ketones or blood sugar or anything but I never ate only adequate protein for several days in row and I reached fat adaptation just fine as far as I can tell but I got very convincing signsā¦
But one can experiment with the fat/protein ratio and grams to figure out what works best⦠I have a smallish wriggle room due to my items and taste and how my satiation works. I eat high protein and more fat than protein in average but various ratios seem to work, at least temporarily. I heard about many people who preferred a narrow range or had odd limits for fat or protein, there are therapeutic ratiosā¦