All the kana are easy to learn if you use mnemonics, though I admit handwriting recognition might be harder. It took me a moment to recall some of the mnemonics themselves, eventually you just see them as they are... For tsu, I can think of Two sewing needles, for shi, I can think of "she has a funny face", for so it's one "so-ing" needle, for n it's a cyclops who can only say "nnnnnn". (https://www.tofugu.com/japanese/learn-katakana/ and https://www.tofugu.com/japanese/learn-hiragana/ have some great mnemonics to start out, I remember only altering a few.)