I took a quick look, when I have time, I'll analyze it more carefully, but I found the whole process quite difficult at first, remembering that I wanted to learn the descriptors to use in the Bitcoin Core console when I need it.

I think going that route makes things a lot more difficult, especially for non-technical users.

And the main thing, I hope someone knows how to answer my initial question and concern, what am I going to do to use the keys from my wallet on the Core in another wallet when the Core crashes?

As now with a descriptor wallet, I won't have access to the private keys, how do I know that I own my BTC's? This point I wanted to get to...