Looking at one of the climb via/descend via publications on faasafety, the altitudes and speeds on an arrival are separate. You are required to comply with the speeds, unless told otherwise. You are to comply with the altitudes once directed, I.e. descend via.
If you are assigned a star that has “descend via until intercepting ___knots,” then once you are on a published portion of the arrival you comply with all speeds unless you are told otherwise even if you aren’t “descending via” yet. This includes if you are subsequently vectored off the arrival. Continue with the speed as published or assigned. Same applies if you are given descend and maintain.
Once you are given descend via the you comply with speeds AND altitudes until told otherwise.
On a related but separate subject, if the arrival only has “expected” altitudes you SHALL NOT be given a descend via. However, a lot of those arrivals have published speeds that do not include “expect”. Those are hard speeds and must be complied with unless otherwise instructed.
https://www.faasafety.gov/files/noti...1-20140220.pdf