Voron would be my recommendation. It ticks all the boxes of what you need it to do. The only caveat is you need to build it, screw by screw (unless you buy a pre-assembled one such as siboor). It also requires printed parts which can be ordered via Vorons PIF program (high quality, printer-verified parts).
Depending on how easy you find it, it will take at least 10 hours to build. But that is part of the fun.
Software and repairability are there. Spares are cheap and klipper is open source. It can work offline but it works better paired with tailscale. You can upload sliced models OTA.
Slicing models will be the easiest part. I'd recommend the basic orcaSlicer set up for the printer of choice and go from there.
Good luck and have fun. 3D printing has become the most addictive hobby I have ever taken up. Be careful with your time!
Second this, if you have the time to assemble everything that is.
On the plus side your Voron won't become obsolete as you can just upgrade it to the next version.
I just upgraded my Voron 2.1 to have direct drive. Having build everything myself in the first place, the decision was easy.
Meanwhile we have a Bambu X1 at work and some of the time I just have no idea why it does not work.