Are you sure?
Almost all manufacturers specify much better than +-5nm.
for example:
Thorlabs specializes in the building blocks for laser and fiber optic systems. From optomechanical components to telecom test instrumentation, Thorlabs' extensive manufacturing capabilities allow us to ship high quality, well priced components and devices for next-day delivery. Optomechanics...
www.thorlabs.com
Thorlabs also specifes <0,5nm for a 350-700nm range which is exactly what a hobbyist would need.
The LR1 is very old and already uses a 3600px wide sensor. (which isn't even in production anymore)
The newer LR2 version is advertised with a much better resolution.
Might be that the "usual 1024" sensors you talk about are long gone history.
The 3600px Toshiba sensor is older than 26 years by now.