There is so many ways this can be done and there’s no one stop solution which fits all usecases.
When you have multiple systems - there’s no guarantee they are ever at an identical state - what if you use different branches on two systems? Using pacserve or pacredir in such case is asking for trouble
To maintain a local mirror of a single branch using lftp to maintain a mirror is the simplest yet reliable solution. You can create service and a timer to trigger the service and thus run the syncs at a suitable interval or you could trigger the sync on demand - that is when the first wave of issues after a major snap has stabilized.
The benefit from doing so is the state of your systems is always known. You will have better control over the stability of your systems.