I'm not sure you could accurately describe a currency peg that is created as a result of a token being redeemable in the underlying asset as price fixing. There is no law saying that a token backed by BTC must be bought and sold at the underlying asset price, it just works out that way because significant deviation from the underlying asset price would cause an arbitrage opportunity: people would start buying and redeeming bitcoins on a side-chain if for some reason they consistently had a lower price and the opposite for a higher price resulting in the price matching again, at least up to the point where the cost of issuing and redeeming becomes a bigger factor.

Having high value tokens on an untested and low security blockchain is a concern but people already emulate a similar risk when they hold funds with centralized exchanges.

In the long term I am aware of 2 obvious routs for true scalability of a single blockchain: lighting network and sharding or approaches that fall into similar categories.

Basically the lightning network is where actors who do frequent transfers dont submit transactions to the blockchain but instead hold onto them. When a new transaction is needed they construct it in such a way that it invalidates the previous transaction and is economically favorable to submit. In this way any number of transactions can be made essentially for free but if things go wrong there is always the possibility to fall back to the distributed consensus of the blockchain at the much higher cost. To form a global payment network you would have a way to form chains of transactions with the same property, with enough people participating it would be highly likely that there would be paths between users what want to make payments especially considering there some actors would act as a hub for many users which would be ok in the sense that you dont have to trust these hubs but not in the sense that they become a target for censorship and data collection (even while a lot of the information "falls off the map" in the sense that a lot of transactions are no longer on blockchain)

Sharding (like shards of glass) is very similar to having side-chains for scalability: miners would mine on their own chains and those chains would be synchronized to form a global consensus but each chain would be running at its own independent speed so they dont have to wait for the global consensus to move ahead. Transactions would be divided up, for instance by the first few bits in the transaction ID. In this way as the p2p network grows you can have the blockchain divided up more and more while maintaining whatever level of consensus you need (just wait until the shard is confirmed on higher levels of what is essentially a tree like structure) Its hard to conceptualize especially since such things are still in the research phase but the scalability improvements are kind of obvious. (note: I'm heavily biased towards Ethereum getting useful sharding achieved first)

Have you done videos on either of these topics or do you plan to find experts in these areas to try and parse out a more understandable conversation about them?