I have shared in another thread my experience of using the Apple Watch Ultra 2 while trekking the Annapurna Circuit last year, which might be a helpful reference. It worked fine and I will not hesitate to use it on my Manaslu Circuit trek later this year.
That said, I use the Watch primarily for tracking health information and logging the hikes. I have not used it for navigation purposes as it was not necessary for the trek; I have a guide and the trails/roads were clearly marked. When I did, I still rely on paper maps and guidebooks.
The few times I tried to use mapping and navigation apps (e.g. Wikiloc and AllTrails, not on the Annapurna Circuit), were frustrating as I tend to explore alternative routes - and the apps would incessantly alert me to get back on to the main trail. I would rather enjoy the walk in peace than fight the apps. Offline maps and GPS worked well enough, though; I just refer to the maps without recording my hike using those apps.