Honestly, even the fancy add-on GUIs will still make these sorts of errors, too. I have provoked this exact same issue and similar, albeit simpler troubleshooting process when using ThunderHub to open a channel. ThunderHub shows a floating point value for sats/vbyte when calculating a proposed fee amount; but then when you submit, the value is truncated to an integer, which will cause your transaction to lag behind half the mempool in a low or concentrated fee rate environment.

What you see in ThunderHub:

What you get in the mempool:

What you need on chain:

I feel your pain. Hopefully devs will continue to iterate and eliminate all these problematic issues so that plebs aren't forced into custodial solutions.