I wondered if it is a common knowledge how to "jump off" the zoom lens hook
I don't think this is necessarily a good idea.
The problem is basically sensor size. With a 1/1.7" sensor, it is easy to build compact and light lenses. Even super zoom telephoto lenses are rather compact.
The downside is that getting "beautiful pictures with a fast prime lens" with wide open apertures requires a big sensor. What you are actually admiring is the shallow depth of field. Sure, you could get a similar effect by using your zoom lens at the long end (200mm) and increasing the subject-to-background distance, but that's not always applicable.
Telephoto zoom lenses for large sensors are cheap, good and light weight - with the caveat that you can only pick 2 of those 3 properties while the third one likely has some undesirable value.
I'd recommend keeping the stylus 1 as it suits your special needs for travel photography and is a tool you have a lot of experience with - you don't want to throw that away. No interchangeable lens camera (which usually have a bigger sensor) will be able to deliver the same experience.
considering stepping up for an interchangeable lens camera while still keeping the travel-friendly size and weight of both a camera and a lens
Is interchangeability really the requirement you have? To me it looks more like you basically want to add the prime lens look to your equipment. I'd definitely look into fixed lens compact cameras with bigger sensors. There are some with full frame sensors like the Leica Q and the Sony RX1 series, but also some with APS-C sensors from Fujifilm.
Some of the above and other manufacturers also offer interchangeable compact / mirrorless camerasystems. You can certainly buy a camera with interchangeable lens and simply just use one lens on it. But then why bother buying an interchangeable lens camera in the first place? As mentioned above, I doubt that you will find an equivalent lens (in terms of price, size, weight, zoom) to your current setup for the interchangeable camera easily.
Even if there was one, you now have the possibility, but also the burden of having to interchange lenses. Carrying a second compact camera might sound counter intuitive for travel, but given that you don't really need more lenses, it might make sense to have a camera permanently attached to each of the two of your lenses. They'd be ready to use all the time. And if you are travelling with somebody else, they could be used in parallel.
update after comments
My wife is a photographer and she wants an interchangeable lens camera, so I imagine we would have to eventually settle down with one, be it a mirror- or mirrorless.
You'll always bring the Stylus 1 along the ILC (interchangeable lens camera) on travel, for the reasons mentioned above. You don't want to miss the picture opportunities where such a zoom is required. If it's your wife who wants to have an ILC, she's likely the one going to use it the most. Guess who's sticking to operating the stylus 1 then? You. You will not get out of any habits by having the option to use another camera that you have to share with somebody else.
Bearing that in mind, I would also like to use the opportunity to step out of my comfort zone [of a zoom lens], therefore I was wondering if there are the known guidelines on how to switch from the super zooms.
It's great to share a hobby with one another, but sharing a camera is no fun. You are going to need your own camera in order to get out of your comfort zone. I'm not sure what your budget is. You could still go for a fixed lens big sensor compact for you in addition to the ILC for your wife.
However, given that your desire to get the "prime look" is not the only driving factor to buy the new camera, chances are your wife wants and needs additional lenses for the ILC. It can make sense to buy another camera body for the same system for you with a prime of your choice. This way you get the prime look that you want, do not have to share the camera with your wife, but can share lenses with her. An older used body might be sufficient for your needs and is cheaper.
The only downside is that all of that is quite a bit of gear and you then have 3 cameras. This likely means you will leave the super zoom at home, which could mean that you miss out on those picture opportunities that ask for such a camera. Of course, this is the best way to get out of your comfort zone. It's a compromise in the end.