Being a twin, I deeply appreciate that my name is distinctly different from my twin's name. Here are some aspects that come to my mind. Choose similar-sounding names if you want these aspects; avoid similar-sounding names if you don't:
Pros of similar-sounding names
can be easier to say quickly, i.e. they flow naturally from the tongue.
emphasize that they belong together, they are a set, they are part of the same family.
Cons of similar-sounding names
risk of teasing.
risk of feeling less distinct, harder to define oneself without referring to the sibling.
I might add more bullets to either list when I think of more.
Writing this answer makes me think that we could also have a question about general factors that could be considered when trying to come up with names for children -- but that's unrelated to this question.
I'd propose to choose differently sounding names for siblings and especially for twins, as it can avoid confusion when you want to call one of them.
E. g. in our son's playschool there are twins which are called Ozan and Rozan.
This is very cute, but IMHO it is confusing for other people (who is who?) and as the names sound extremely similar it is also difficult to clearly call one of both.
You know, in the moment, you will call them by each-other's names sometimes anyway. I am three years older than my sister yet mom always referred to me with her name and vice-versa if she was upset, in a hurry, etc. My Grandmother even once called me by my Dad's former dog's name. Go with names you really like and don't worry about it being confusing. You'll mix their names up anyway and - you'll be using them a lot so you'd better like the names.