What did you do to save time as a startup founder?

Hire excellent people, that you can trust to do the job well, on time, without constant monitoring.

Then you can have family time knowing everyone has each others back.

I've spent several months very far away from everything and focused purely on coding and my mental well being.

Use tech you already know. Accept its limitations. Compared to how much time people spend thinking about it, tech stack is likely far less important than most other choices.

I've got this wrong before, I've got it right before. A new company sounds like a good opportunity to use new tech, but It's disarming if you can't solve a problem because you haven't mastered your tools yet. It slows progress if you have to learn on the fly. In contrast, using tools you're already comfortable with gives you really good momentum.

As the author of the SaaS boilerplate https://achromatic.dev my business is saving development time :)

Other than that automate more, be it with own tools or existing ones.

Most time consuming and most important in startup is gather first time clients, so use any possible things to got clients for free (or semi-free, for example on venture events, or become part of some platform, like consoles in gamedev) or to just buy leads traffic for example as pay per click.

All other things are very different, very specific for each startup, and depend on what is your target environment, what is your kernel tech, etc.

delegate all the work.

Cut things to as slim as possible. Reduce/outsource all non-core verticals. This will likely end up with an "incomplete" business model. It worked for pretty much all of FAANG and most of their acquisitions. Netflix was overly reliant on partners. Google/FB relied on an ad network that they had to build themselves. Amazon pioneered "no profit" businesses, and they haven't gone global, letting competitors grow huge in foreign markets. It worked for YouTube, WhatsApp, Android, most of the huge acquisitions.

Don't think of scaling in terms of user count, employee head count, revenue. Think of it in complexity. You can scale pretty easily in a small market until you get 90% of the market. It's by being clever that many people start to scale poorly. You know you're scaling poorly when you're hiring people just because you're hiring people, and when you spend more time communicating than doing the work.

You can't move safely as an entrepreneur. Even as a bootstrapper, someone will come in and buy out your market or siege you out of it. There are fairly safe red ocean businesses though, e.g. games and "specialist spreadsheets" like CRMs/ERPs.

Family time shouldn't be much of an issue; it's other hobbies that suffer. You should have a decent amount of time left over once things click.

Curb your perfectionism and keep things as simple as you can. This applies not just your business, but life as well.

Also, take care of yourself. Not getting distracted is difficult as it is, but will get impossible once you are exhausted.