I was full keto a few years ago. I worked very well for me, but it required a lot of discipline (which seems to be in short supply now).
I still generally only use low carb snacks on the bike.
Primary snack food is almonds, cheese (small blocks of cheddar individually wrapped, or hard cheeses like Parmesan) & dried sausage (South African Droewors or German Landjäger is best - that Peperami stuff is just wrong!)
For longer rides where I want to carry carry more of my own food to be independent of what I can find at the controls I take "
Banting bread" made with ground seeds, eggs, with added cheese & bacon - all very high fat, low carb.
FYI: There is a Keto thread over in Health & Fitness -
https://yacf.co.uk/forum/index.php?topic=67736.0