When tidying sentimentals I came across many items from my home country which I had moved halfway across the world several times. For me it brought another complexity. I kept these items but have never used. They no longer bring me joy but getting rid of them feels like I toss of heritage.
Marie Kondo: I think you have answered your own question, when you wrote that these items “don’t bring you joy”. You are your own heritage, and what your life in Germany meant to you is something you have with you at all times, you don’t need items to inform you. But if you want to keep a small selection of these items to show your children or someday maybe your grandchildren, then of course a small scrapbook dedicated to these items is a fine idea.
Me: I ended up keeping only one item which is a handmade cup with my name. I use it for salt and placed it next to my stove for everyday use. It sparks joy when I see it.