ffs, this attitude causes massively more problems than it solves.
1. You can always change later. Uber switched from Postgres to MySQL when they had already achieved massive scale.
2. You don't know what scaling problems you're going to get until you've scaled.
3. Systems designed to scale properly sacrifice other abilities in order to do that. You're actively hurting your velocity with this attitude.
4. Every single expert in the field who has done this, says to start with a monolith and break it out into microservices as the product matures. Yet every startup is founding on K8s because "we'll need it when we hit scale so we might as well start with it"
5. Twitter's Fail Whale - the problems that failing to scale properly bring are less than the problems of not being flexible enough in the early stages.
Build it simple, and adapt it as you go. Messing up your architecture and slowing down your development now to cope with a problem you don't have is crazy.