Absolutely. Anyone senior should be able to fairly quickly get a handle on the requirements for a particular project and put forward a well-reasoned opinion on

Absolutely. Anyone senior should be able to fairly quickly get a handle on the requirements for a particular project and put forward a well-reasoned opinion on an appropriate tech stack for it. There might be some blank space in there for "I've heard of X and Y that actually might fit this use case slightly better, so it's probably worth a brief investigation of those options, but I've used Z before so I know about the corner cases we may run into, and that has value too."