This was contentious from the day Dorico came out. Basically, Dorico wants you to have as much flexibility as possible in the differences you may want between score and parts. The problem is that while they have this brilliant system to override enharmonics where changes in score automatically reflect in the parts, but not vice-versa, they did not implement such a system for properties panel overrides, at least not for a large amount of properties (for example: dynamics suffixes and prefixes are automatically propagated). They have acknowledged that they went too far in having Dorico not updates part layouts for such a large number of properties overrides, and therefore implemented a manual system of propagation as a stopgap measure (and they made the stopgap aspect of it very clear). They also have said that they will develop a system where the user is aware of what is propagated and what is not, and review the overall choices that Dorico makes in propagation.
In the meantime, Propagate Properties is a pretty good interim if you do a couple of things. First, ascribe a shortcut to it if not already done, and then, since the majority of Write Mode overrides are generally wanted in parts, you can simply finish the flow, type ctrl-a to select everything, and then invoke the PP command. This is very quick. I do Engrave mode overrides one by one however as those are generally very layout specific, and selecting everything in Engrave Mode is very taxing to the system in a large flow. But since you are using Elements, you need not worry about that for now.
In the end, after manymanymany scores created with Dorico, I have come to appreciate the basic philosophy of keeping things independent from score to parts. It has helped me do things that are otherwise difficult or impossible to do in other software, but this is one of the rare cases where the implementation was awkward and only fit the minority of cases. Rest assured that they are working on it.
