[munk-a]

Backups are most definitely a necessary part of any persistent datastore that is accumulating value for your company. Sharding is something that becomes necessary at scale - having it in your toolbox is a really good idea - but it doesn't come up for most folks. Failovers are the least valuable of what you've mentioned IMO since downtime management is something that even very mature companies have a lot of flexibility with.

SQL is a pretty easy language to learn - you can get pretty much everything working right with some SELECT, FROM, WHERE, GROUP BY and subqueries alone - the more arcane dialect components of SQL (like HAVING - gosh I hate how easy to misunderstand HAVING is) are things you can grow into. But basic SQL - it works and has worked fine for decades - I strongly dislike tooling and languages that go on crusades to make a better SQL.