I look at the eyes. If it's light blue it's Alyosha, if it's purple it's Jurij

This one comment saved me, you own my life buddy

Also Jurij has like little dark circles or eye bags it seems as to give the readers some sort of foreshadowing of him having to take a much darker role that what it appears like weird that alyosha never truly kills seems Jurij is the gentleman and takes that role

You can also look at the parting Alyosha part his hair on the right side, while Jurij part his hair on the left. Here's a page where they are side by side...but I still prefer the eye method

https://www.mangago.zone/read-manga/the_first_commandment/uu/to_chapter-25/pg-31/

I just noticed it after you pointed it out .... Jurij is also a bit taller I think

Y'all are so observant my gosh, I'm the one stupid af

Nah your good...It's really hard to tell them apart.

Thank you because those hos look like twins lol