1. How to minimize probability getting "no path found" error when try to receive btc, besides opening up more channels? Is there a guide to show how
which channel is better than the others. Or is there a node network map to see rx path?
There's a famous lightning node explorer that you can use to check if a lightning node has many channels and capacity.
Also their uptime, usually those at the top are reliable enough.
Here's the link:
https://1ml.com/ 2. If I can receive without problem from a channel, is it possible if it gets "no path found" in the future?
There's always a chance, since it also depends on the on the remote node's status and the payer's channels, not just yours.