Has moving baby in room with sibling helped or hurt?

Been dealing with frequent wakes (usually every 2-2.5 hours, sometimes 1 hour if she’s sick or teething) with my 11 month old since she was small. Ive mayyybe gotten a few 4 hours stretches, but it’s been a while. She’s EBF, does not take paci, sleeps in crib in our room..I think the issue is her not being able to self soothe, but curious of others experiences before burdening my toddler. Considering gentle sleep training but want to hear others’ experiences.