Its taking 1 hour and 20 minutes to complete a full clean build on my single node.

In fact, I want to use Open Source tools for this purpose, a commercial solution is not an option tbh.

Thanks for suggesting Incredibuild, as I make a fast search, I see that there may be some open source alternatives (eg. FASTBuild) to Incredibuild but not sure this can be used to build the LineageOS.