Why is the Insta360 GO 3S - Grainy/Noisy

I just recieved my Insta360 GO 3S (first time purchasing a Insta360 Camera), it's either I'm doing something wrong or the camera by design is really grainy.

I inititally tried it at night (indoors) but I assumed maybe it's because of the low light that there is noise in the video, however I tried it today in the morning in a very well lit area and once again there is noise.

Decreasing or increasing the ISO (experimenting) has not made a difference there is always noise in the video. I only purchased this camera because it had the 4K capability but what is point in having a 4K camera when the noise diminishes the quality. My plan was to use it alongside a well known brand pocket camera but If I was to use the GO 3s alongside this pocket camera you can tell there is a day an night difference. I also decreased the sharpness, In post production I couldn't find a way to reduce the noise.

I hope it's just a setting that I'm missing out but I can't seem to find this. if I try in freeshot mode the quality looks much better.

Another odd thing, yesterday the moment I charged the device for the first time I got the following message "charging paused, it will resume once go 3s cools down" - is this normal? (no video recording had taken place)

Update: Just tried it now again in 2.7K (50 Frame rate) and there looks to be no noise (smoother), I will be dissapointed to know having a difference in 20 frame rate and lowering the quality allows you to have a smoother quality video, because then it defeats the purpose of actually getting the GO 3S, as I was better buying the GO 3 as I wouldn't use an video quality (4K) that creates noise.