Cool! Just knowing " all content inside code blocks doesn’t update, because they’re not metadata" tells me what is possible and what is not! And the reason you give makes so much sense. Thank you so much.
The best alternative, or maybe even the best solution, is a Global Total-Vault Search and Replace function – one that a lot of people are looking for: Global (Mass / Vault-wise) search & replace
If/when we get this functionality in Obsidian, I hope it includes a preview of each match so I can see each one before I commit to replacing it.