mmm Idk if its a self insert because after Run away with me, Girl! she had two successful series; And Then the Heroines Are Gone (ongoing) and Annoying and Cunning Sisters (finished). But neither are yuri, in fact Battan has never worked in a yuri magazine, mostly josei and seinen, so I think she just has a slow but constant rhythm for work.
plus My Sister's Friend was published during Run away with me, Girl! was ongoing and that’s is very good