Fermented foods are indeed a miracle food for our guts! I haven’t tried sauerkraut myself yet, but I brought back a few good size jars that I bought at street market in Poland. Seeing how easy it is to make my own, I might try it myself too!
I do however make my own kefir and like you, I can feel the difference if I don’t drink it for couple days.
It is amazing how different I feel if I have not had some for a while. I make my own Kombucha too and drink that almost daily. Glad you are doing so much to help your gut heath too.