I have one spare drive that I store videos on. All downloads first go to this drive.
I tend to do heavy things, such as record gameplay footage, watch movies, and the like. It still seems high though.
I was about to go research ways to drop routine writes to the drive, such as browser settings, but I figured I'd ask here first before I waste my time.
Watching movies from a local file is read activity which your SSD does not display.
However if you are streaming movies or video, there is a good chance they are being copied onto your system drive in a buffer before playback. Even if that buffer isn't big, it is constantly being replenished from downloaded data. You can easily verify this by starting Task Manager, viewing Disk Activity on your C: drive, opening up a site like YouTube and noting any drive activity as you watch a video. Try increasing playback resolution to 1080p or 2160p to see how that affects disk activity.
Streaming audio is similar but the bitrate is so low that it really won't contribute much.
Naturally if you download a 10GB movie file, that's all write activity until the download is finished.
As for recording gameplay footage, that's also write activity since you're basically creating a movie file. Depending on how you have your game play capture settings configured, this could be one of the bigger culprits. Just recording your gaming for ten minutes, stop, note the size of the recorded footage and multiple by six for the hourly write speed of that activity.
Unless you are watching streaming video (YouTube, Twitch, etc.) your web browsing activity shouldn't create major volumes of disk writes.