While tricky, running Windows XP isn't impossible, even in 2024. Using a variety of tools, including abandonware, open-source software, and other programs, we can set up a very capable workstation. You don't need to be a programmer writing your own software to make it function - Google's your best friend, or if not Google, then DuckDuckGo, or heck, an actual book on the subject.
As far as back-ups go, there's really no better option than backing files up manually. It encourages you to stay organized, and to keep the files you need (data hoarding is perfectly fine, but just keep it organized and easy to copy - if you can't navigate it, sort it. If you don't want to sort it, delete it.)
Personally, I run back-ups every week, and have two redundant copies - I use external drives as per lack of space / resources, but if you have a NAS, all the more power to you.
If you're running Windows XP in 2024, whether by choice or by circumstances, you're likely a connosieur of older tech. Fear not, for the great thing about Windows XP is that it doesn't take up 80% of your 80GB hard drive. I have an HP office machine (bought used) with an older i5 processor, but plenty of RAM and storage (4GB and 1TB respectively.)
For my data hoard, I have a solid 10TB with redundancy (20TB of drives), but I try to keep it compressed and sorted, such as to use as few resources as possible. Hey, electronics ain't cheap, and they won't be getting cheaper. If things go the way I think they'll go, stocking up on hardware and data will be useful. Moving innawoods and generating your own power / growing your own food too. By the way, don't fall for the bit about "you need 50kW of solar panels to survive" - minimize your energy use first, become sustainable, and only then pursue self-sufficiency. I'd suggest sharing data with your neighbours, or, if you're tech-oriented, set up a little server for friends and family and neighbours. Heck, if you're sufficiently tech-savvy, consider building a larger, off-grid local network with Ethernet cables and routers. It'd be fun, believe me. I'm building one right now.