For me it all depends on where I'm going and what I plan to do with photos. For puttering around the Caribbean I ight just bring my cell phone. I have an older model Samsung (S20). Obviously easy to carry anywhere and good enough for casual photos around the ship or at the beach, which will be mostly viewed on a computer monitor or cell phone. Occasionally I'll bring a "serious" camera because I like to shoot sunsets, but I will not carry it to the beach or to a touristy town. If we are going on a cruise for "sightseeing" I will bring a "serious" camera, with appropriate lenses, and if needed a tripod and flash unit. we also take many non-cruise trips either to national parks or other cities/countries and I will definitely bring a "real" camera.
I have been using a Nikon D750 with excellent results for years. Lenses 28-105mm zoom, 70-200mm zoom (sharp as a tack but an absolute brick to carry), and 28 mm prime. Benro tripod, third party flash unit, UV, ND, and polarizing filters, power pack. This line up feels fine weight wise when shooting at a single location, or when driving from spot to spot and shooting from a point near the car. However this line up is getting heavy when walking around cities and parks. Was thinking about trying out a mirrorless system, and was able to acquire a Nikon Z7II with a Z mount 24-200mm zoom, as a retirement gift from my Company (instead of an expensive watch). Have used this camera and lens on my last two trips with excellent results, very sharp images. Comfortable to use both with respect to weight and control placement.
One item I don't think was addressed in the above posts was weather and light. When visiting a location for a short duration one is at the mercy of the weather. Cloud cover, fog , rain, smoke etc. can make for dicey shooting conditions, and possibly limiting photo quality. Lighting drastically affects photo quality, sometimes I will be shooting around mid-day with direct sunlight., because that is when I am at a specific location. As I assume for most of us travel photography is an avocation, and one doesn't have the luxury of spending an entire day, or at least many hours in one location waiting for the shot.
Just returned from week cruise to Norway for Northern lights. Link to photos.
https://img.gg/li99WfI
shot aurora photos with D750 and others with Z7II