If it’s 6.2 MB and not 6.2 Mb (‘B’ = 8 bits = 1 byte, ‘b’ = 1 bit = 1/8 byte), then that’s way more than enough; the max is 3500 Kbps = 0.4375 MBps like you said.
Though I looked at your stream, a little more closely this time, and IMO it doesn’t look like there’s anything wrong with the quality. Even for big streamers, the quality goes up and down depending on how they’re moving and what the map is. I may be wrong (and feel free to tell me off if I am, i could have missed something big), but it seems like you might just experiencing a completely normal level of quality loss from the compression. It may seem at times like some other streams are more crisp, and there may even be a few that are, but the stream will almost never be the same quality as what you see on your screen unless you’re standing still; and it probably seems much more pronounced too if you try to compare it to what you see on your screen while playing.
For example at 1080p stationary:
you vs phantoml0rd
And at 1080p moving:
you vs phantoml0rd
<img src="/uploads/default/620/3e2a8135645a8780.png" width=“240 height=“135”> <img src=”/uploads/default/621/5e8b9f6df9537fc7.png" width="240 height=“135”>
And at 720p kinda moving:
you vs godazed
<img src="/uploads/default/623/3c83d6e5db678179.png" width=“240 height=“135”> <img src=”/uploads/default/622/c8044c2b6cbd77a0.png" width="240 height=“135”>
No difference in quality from what I see, in any of them.