Hey Julian,
I went the DIY route myself and had a great experience with a kit from The Guitar Fabrik. The wood was solid, the neck felt right, and it made a perfect foundation for some nice upgrades. I replaced the electronics too, and it came together better than I expected.
If you’ve already got a plan for the pickups and preamp, you’ll probably have a lot of fun with it. These kits can definitely be worth it if the core is decent.
You can check them out here if you're curious: https://guitarkitfabric.co
Good luck with the build. Would love to see how it turns out.