Honestly, if you look at old German documents written in the Kurrent cursive system, it's about as bad. For the most part, it's just a matter practice and familiarity with the writing system.

Лишин though, that's definitely a rough one.

The latin cursive scripts differ country by country. And reading old letters, even if it's in my language, is very hard. The letters looked differently. A proficient writer would write them consistently but to read it, you're looking for "distinguishing traits", not for the letter shape as depicted to learners.