unity – How to align prefab to a accurate position with the best practice?

I’m making a plumber game, I have a pump prefab, and pipe section prefab, which allows the user to connect the pipe during game, the pipe needs to be connected seamlessly during game, which means pipe prefab needs to be aligned in pixel level, please check below
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User needs to add more and more pipe to connect the with each other, pipe is fixed length prefab.I’ve got choices,

1.Is the pipe prefab instantiated during game play a good practice? Because it might have many pipe prefabs, if the pipe goes a long way to another position, than there will needs to be so many pipe prefabs, compared to have procedrually generated pipe mesh during runtime, then a long pipe will not have to be cut off to the same small pieces?Which is good way to adpot?

2.If I use the same pipe prefabs to fabricate the piping system, how to accurately connect each other in pixel level, I can make the whole piping system in blender, then cut the system into pieces as my prefabs, then import to Unity as my first choice, this can do pixel level connection, but it seems to have better choice solely solved pixel level connection in Unity?

3.If I do it by generating the mesh during game play, then it could be complex especially it is hard to make elbow pipe mesh during runtime, or could you please advise me of some known library or package can do the work?