Which model of HomePod is it? All of mine have the option. I’m sorry I’m not able to test remotely for you. I only use it while at home. I use it a lot as sometimes my Mac won’t connect to HomePod. A restart always fixes that.
I have 7 homepods; 2 gen 2 big ones, 4 OG big ones and one mini. I also have 2 Apple TV 4Ks. So that’s 9 HomeKit hubs. Sometimes it can make a difference on which Hub is acting as the main connected one. This can be chosen remotely in Home Settings - Hubs & Bridges in the Home App, if you’re able to do that? This might test what you can do remotely.
A couple of weeks ago my HomePods were acting up and I tried every troubleshooting step there was and nothing worked. So I signed out of one Apple TV, restarted that and signed back in and voila , it was fixed. This resets HomeKit, at least in the Apple TV. I don’t choose which Hub to use, I let it choose automatically, as that has always worked. Some people swear one works better than others, why doesn’t Apple let us choose? So Apple finally added this as a feature a few updates ago. The HomePods originally never let you Restart remotely, again this was a feature they added later on. Apple does read all feedback and consider requests if enough people pester them about it: Feedback - Home App - Apple