i get the joke but like... elka is probably bi, right?? probably? it really just kind of seems like bi erasure :\
hi! i get your concern since i am also bi, but i would argue that elka isn’t bi. instead, she is a lesbian suffering from compulsory heterosexuality.
elka is completely focused on her foresight. she is convinced that she is destined to be with nils since the doom family has never had any wrong predictions. due to this, she desperately tries to keep her relationship with nils working even though he treats her like garbage such as forgetting her name when he is rebrained without her, reminds her that she isn’t supposed to talk when both are rebrained, and insulting her many times on campster. it’s definitely not a healthy relationship. nils even bragged about getting to first base with her on the tree stump, which i’m very sure elka hated.
elka goes with jt because she wants to get nils back by making him jealous. this is evidenced when she meets with nils to rile him up by using jt’s vernacular while nils mocks her by saying he made out with lili, which of course isn’t true, and they proceed to bicker over who is really jealous. of course, her relationship with jt isn’t healthy because jt isn’t committed, and elka threatens chops on campster and in-game to stay away in order for her "get-nils-back-by-making-him-jealous” plan to work. she is left alone when jt realizes elka has been hurting chops, forcing her to relapse to her relationship with nils in a sorrowful tizzy.
her relationships with boys, nils and jt, have been extremely bad. nils only wants to use her, and jt was part of her plan to get him back. that’s why i believe elka is suffering from compulsory heterosexuality due to her intense faith in her foresight as it predicted she will end up with nils in a clearly unhappy relationship (like her parents, which she DEFINITELY doesn’t want).
i think when elka realizes that she doesn’t have to be forced to like boys, she will be much happier with a girl who will respect and cherish her. she’s already shown to have pretty good friendships with milka, crystal, and lili, so it’s really easy to come to the conclusion that she is a lesbian suffering from compulsory heterosexuality.