Your concerns about network trust are entirely unwarranted. In the bitcoin whitepaper published over ten years ago, before the software was even written, Satoshi explains how a trustless network might be created via Proof of Work.
On the topic of price fluctuations, I'd like to point out that not only are there a plurality of stablecoins pegged against and collateralized with dollars, there are also synthetic assets like DAI which follow in Satoshi's footsteps - using game theory, economics, and finance, to novel and practical effect.
I highly recommend reading the Bitcoin, Ethereum, and DAI whitepapers (in that order).
https://bitcoin.org/bitcoin.pdf