Are you implying Riza would've let Roy die and viceversa? I'm sorry, but comparing Eruri to Royai is just so silly. Royai were always truthful with one another, and there to help each other during their times of weakness. Eruri is completely the opposite.
I’m pretty sure Riza held a gun to the back of Roy’s head when she thought he was at risk of losing his humanity. And I’m pretty sure if a situation occurred where letting Roy die was an ultimate act of love, she’d follow through with it. Happily, they never faced that situation.
I’m also pretty sure the whole “help each other during their times of weakness” applies to both. Erwin gave Levi a life and a purpose. Levi returned the favor a dozen times over but most significantly in chapter 80.
But mostly, the person who sent the ask wanted my opinion so I gave it. You are perfectly entitled to having an opinion of your own and if you send me a message off anon and I’d be happy to ask your thoughts on Eruri and Yumikuri. But as it is, these are my two favorite manga relationship because of how they were forged and what they represent. I see differences, but also many commonalities between them.