Having difficulty understanding how dapps work on the network.

Sorry if this is a foolish question but I can't quite find something that explains it in a way I can understand.

I get that the network works together to reach a consensus on the state of the blockchain, basically who owns what and what transactions occured when. What I don't understand is how other apps work on that network. Doesn't that put strain on the network that could be used to lower (in the case of Eth) gas fees?

Again, I apologize if this is a question answered elsewhere but I can't find any answer that I properly understand and am very interested in how this all works.