Yeah you’re right, NXP does lean into Yocto. The IMX line has good support with it. You might have the flexibility of going with the community built BSPs and/or vanilla Linux kernel, if you don’t want to rely fully on NXP written software. I’m not 100% certain on the support for your boards under the community supported repos, so you’ll have to look into your exact use case. But it does give you some options.

What platform are you trying to target? That makes a big difference in what kind of support is available. The more uncommon your hardware is, the more work you will have to put into building the distro. If I recall, Debian does provide some documentation on bootstrapping new hardware. You could try going that route. Yocto and the bitbake recipe syntax does have a learning curve in the beginning, but it is a really powerful build system, and probably would save you a lot of headache. Especially if you want to keep the image updated or extend the capabilities in the future. If you already have a cross compiler, bootloader, and a kernel for your target, you’re halfway there. Then all you need to do is figure out what applications you want for your distro. But if you’re going to have to build that all from scratch, Yocto will probably save you a bunch of time when you have to recompile and redeploy.

This layer looks kinda dated and not maintained. Have you tried building meta-riscv? I have had success building a custom image for the visionfive 2 using the meta-riscv layer. (Same SOC as the pine64) I would start off with just the minimal core image. Not sure if you’re are looking for graphic support, I was only interested in a headless configuration.