There is no “they” able to change the algorithm.

A consensus of miners is still a "they".

Even a unanimous agreement of all miners would be unable to change consensus rules. These rules are not set by miners.

Miners choose which version of the software they run. The software defines the consensus rules.

If sufficient mining power prefers software versions with specific consensus rules, the rules are effectively changed. By a "they".

This is simply not true. BTW I was a bitcoin core developer for many years, and am one of the few people who have actually changed bitcoin’s consensus rules.

If a quorum of miners decide to run hard fork changes, then they just disappear from the network once the changes trigger. No miner can force a user to change their consensus rules.

A soft fork is different. But increasing the bitcoin issuance can never be a soft fork.