I’m guessing that she’ll hold out longer than you want to wait and that you’ll end up feeding tilapia again. Lol.
I was fortunate that my endli didn’t take long to switch from live red wigglers to pellets. Although, I’ve heard members mention that it won’t take them long to go for a dirty sock. Lol.
Now, my endli will eat pretty much anything it can get ahold of, which is mostly Massivore.
Have you tried mixing the pellets and frozen tilapia together and dumping them all into the tank? It might help get some of the tilapia taste onto the pellets. It will also put the pellets and tilapia in the same proximity so that a pellet might get eaten with the tilapia by mistake. I’m pretty sure that’s how my endli got started on them.