I’m not entirely sure on the specifics. I think PinkTea mentioned in at least one of the games that they’d hit an upload limit of some sort but it’s still a bit vague as to the details.
I’m aware of the subscription support options just my continuous support budget is a bit stretched already. Would love to buy RoB (as I did I think all of their previous work) when it’s out but definitely not going to do it through steam either