problem is persistent... and i don't want to have a refurb
Not sure what you mean by not wanting to "have a refurb" but if you mean you don't want to go to an Apple store and get a replacement that is a refurb, why not? If it's functionally and cosmetically the same, what's the problem?
Either way, if you can back up to iCloud, you could try doing that and then restoring as new, seeing if the problem clears, and then restoring again from the backup to see if the problem remains cleared.
Otherwise, besides what those links suggest or going to an Apple store, I don't know what else to recommend.