Notion is not famous for being the lightest and fastest tool ever.
Despite this i think Notion has still the best writing experience on the web (i am even writing this blog post from Notion right now).
If Notion managed to slim down the Js bundle loaded on the client then it would be by far the best writing experience on the Web.
The total resources downloaded are even worse, 12Mb in total
Why this is a problem
This means that if you are using Notion as a replacement for a website like a careers page or a terms & policy page (i have seen that a lot) you will be lucky if your users manage to load the website.
On mobile i also noticed that sometimes the Notion pages won’t load the first time and you will need to reload the page to see the contents.
I frequently encountered this problem using an iPad 2018, i can’t imagine how bad the performance must be for a low end Android device.
A temporary solution for public facing Notion pages
If you want to quickly improve the performance of some Notion pages you are using for public facing content then you can use a tool like Notaku
Notaku generates websites from Notion pages, you can use it to build docs, blog and changelog websites and it also has a template for Simple layout websites that just looks like the Notion default layout.
This approach will make the total resources size of your pages around 1.6 Mb (considering non blocking scripts) and a LightHouse score of 99