[outworlder]

Have you got any credit cards? Get one. Before trying the crappy "secured" cards, try a Discover, they seem lenient if you don't have cards yet. Stuff it in a drawer, add something small to it, such as Netflix, setup autopay, forget about it.

Your credit score will slowly increase. And at no cost to you (other than the time to setup this, which can be minimal if you can get approvals online).

You can (and should) live within your means and that's fine. What creditors want to see is that you have access to credit and you use it responsibly (eg, paying on time). You don't actually need to use any of your available credit.