If you need a lightning open or close to confirm in the very next block, you're doing it wrong ;)
Discussion
Also usually true for sending onchain out of the node, but I can’t help but notice it’s a small inconvenience to always have to check a fuller mempool just to verify it won’t actually take a week or more.
So far the discrepancy between my two nodes just has about a 15-20% different in the min fee for the next block but it’s possible that may delta surge irregularly in the future