Why is it every time I upload a rendered renoise track to Soundcloud, the volume is so low?

[TNT]

@basefuc

I render it to .wav and the render sounds great, but when I upload it, it sounds very wimpy and underwhelming due to low volume

To turn up the volume should help.
I never experienced what you describe on SC or anywhere else.
You could also check this thread. Everything you need to know about LUFS is in this thread.