I am chiming in because I have seen many of your posts and you are trying so hard. But I am not sure you are objective of how your channel might look to others.
In my view, you have "authority" on Nepal simply because your channel name and every video I see on that channel is about Nepal. It isn't going to be a stretch for YouTube or anyone else to figure out you are about Nepal. However, this channel only has 12 videos. That is not a lot. I know you have the other channel which has MORE videos but I will speak to that further down.
The thing I see is that you are making very niched videos that relatively few people will search (or might be interested in). There is nothing wrong with owning niches because there are search niches I target as well. But I have no illusions that those niched videos will ever get HUGE numbers of views. In my case, most people have heard of Atlanta, the metro area where I spend a lot of time. But most people have never heard of Johns Creek, the area I work. If I make videos about Atlanta, the chances of my getting higher numbers of views are greater than videos on Johns Creek because few outside locals or those doing very specific research would know about it. Similarly, if I make a video about Georgia or Florida, the audience is even broader than if I covered a landmark in either place.
Your titles (as the other titles from your other channel when I last visited) are very niched. You are hyper-focused on very specific things. I venture to say most Americans don't know about. If you don't care about American viewership, fine. But my thinking is you want to find an audience beyond just Nepal. Maybe Europeans, I don't know your preference. But you need to figure out what audience you want to target. You cannot say "everyone" because that won't happen. You try to target "everyone", you will get very little or near nothing.
You say you want more views about Nepal but most people need to be educated about Nepal and know where it is and what it is about before you can ever get into the minutia of fairs, landmarks, events, monuments, etc.
I think you have plenty of authority. You might need to reconsider how OTHERS look at Nepal and compare that to your expectations of how many views and subscribers you want. You need more videos that have titles that are broader in nature.
"5 Reasons to Vacation in Nepal " is one example you could try. "How much does it cost to travel to Nepal". "Where the heck is Nepal?" "The 5 Best Food in Nepal". "3 Reasons Why Should You Care About Nepal"? And you have to do several videos that are high level, not just a couple, otherwise your content will only appeal to a very audience.
All the search phrases and search words in the world are not going to help you unless you also think about the CONTEXT and audience you desire to watch your videos. It is our jobs to connect our content we want to create to the viewers we want to attract.