Anybody who has a "bottleneck" caused by a table with a few million rows is functionally incompetent. From any half-modern database's perspective that's "tiny".

Anybody who has a "bottleneck" caused by a table with a few million rows is functionally incompetent. From any half-modern database's perspective that's "tiny". Any reasonable production machine would be able to fit (at least the important parts of) a million row table in memory. Even if this is your hobby project running on a RaspberryPi Zero, you'd have at least the index in ram. Either you don't care about that query's runtime (a perfectly valid approach if your use case is "this creates a report after COB on Friday that needs to have completed before 9am Monday morning"), or you need someone who knows what they're doing take over from you (also a valid approach if this is in your tech demo or POC, and you're the Technical Founder who's now out of their depth and needs a proper engineer to build a scalable product for you).