QGIS is always a little more difficult than expected. Even as someone with a masters in GIS, its still hard for me to remember where they put things or how to do it. Its extremely powerful but can be extremely frustrating too.
GeoJSON is unfortunately one of the worst formats to keep the data you are using in. Its great for transport and interoperability, but there is no way to index the data in the format. It doesn't matter if you are only drawing a few thousand points, it is still looking through all of them to see which ones to draw.
GIS is awesome, and don't let one tool get you down. If its something interesting to you, there is a lot more to it than just QGIS. Part of my pain with QGIS is because I rarely ever use it so I forget what I learned last time. I spend most of my time purely in python, and don't really need to.
GeoJSON is unfortunately one of the worst formats to keep the data you are using in. Its great for transport and interoperability, but there is no way to index the data in the format. It doesn't matter if you are only drawing a few thousand points, it is still looking through all of them to see which ones to draw.
GIS is awesome, and don't let one tool get you down. If its something interesting to you, there is a lot more to it than just QGIS. Part of my pain with QGIS is because I rarely ever use it so I forget what I learned last time. I spend most of my time purely in python, and don't really need to.