Or rent a bare-metal machine from hetzner with 2-3x performance per core and 90% less costs[1].

[1] Various HN posts regarding Hetzner vs AWS in terms of costs and perf.

Scale-up solves a lot of problems for stable workloads. But elasticity is poor, so you either live with overprovisinoed capacity (multiples, not percentages) or fail under spiky load which often time is the most valuable moment (viral traffic, Black Friday, etc).

No one has solved this problem. Scale out is typically more elastic, at least for reads.

As mentioned in those threads, there is no SQLite WAL corruption if you have a working disk & file system. If you don't, then all bets are off - SQLite doesn't protect you against that, and most other databases won't either. And nested transactions (SAVEPOINT) won't have have any impact on this - all it does in this form is reduce the number of transactions you have.