Similar, read Crime and Punishment earlier this year and it took me a few pages to realize two different names were the same character. Felt silly when I realized lol. Also just started Brothers Karamazov, but decided to switch translations and am waiting for new copy to arrive.
A thought but maybe switch to the Idiot instead. I think of all the Dostoyevsky works the Brothers is the least enjoyable one. Keep it to the end or else it may suffocate your interest and prevent you from reading some of his greater works.
Nothing silly about it. That’s a very common thing people have to get used to with Russian literature. People have several names they go by as well as nickname variations of those names, and different people based on familiarity will use different ones. So you can have a single character referred to by 3-4 different names in a single work! It also doesn’t help if one of their nicknames resembles somebody else’s name lol