I feel that New Horizons has an unprecedented degree of freedom in customization.
And that was very exciting for me to anticipate. The ability to terraform and raise the ground or change the course of rivers, decorate outdoors with furniture usually meant for rooms, craft your own decor items which are again customizable... the possibilities are certainly near overwhelming. I can see how it might translate into stress for some players.
For me, it's manageable because I know what I like and what I don't like. So, for instance, even though there are so many DIY options, if I don't like a particular set, I can decide to
not want to collect those items in the set, since I'm not going to use them. Collecting any DIY set isn't easy. You need to spend time and effort doing it, and then on top of that you need some luck, especially if the DIY recipes come in the form of balloon presents. (Or Pascal.)
The state of too many choices, for some, translates into the inability to make choices. But, if you know yourself well, and know what you like and don't like, it will help you see that you don't have to choose to do everything. Or anything particularly popular.
Also, I don't have a competitive streak. I feel that I don't need to be among the first to complete a fossil/bug/fish/sea creatures/art collection. I don't have to catch or find everything within a season. There's always next year. I don't have to rush to "finish" my island, whatever that means. I like playing the game at my own pace. Because my game is my escape from the stress of real life. So I exempt my game from having the same rules that usually apply in real life, such as deadlines.
If I don't feel motivated to do anything about my island today, it's fine. I take a day off. I do only what I want. I put my game away when I'm done. When I'm motivated, I know I will get things done, and it will feel good.
It's all too easy to get influenced by hype and popular trends, by what people are talking about on forums and social media. If you feel overwhelmed, stop and ask yourself: Am I doing this for me or am I trying to impress someone else/be like someone else? What do I like? What don't I like?
It's okay to be yourself and enjoy the game on your own terms.
I apologize for the wall of text. The older I get, the longer I take to say anything.
