You "and Greg" constantly spit out the same clean, unplug, and 2 minutes schtick every chance you get.

Let me tell you something. Storage space is rarely an issue, and you should not be cleaning caches and thumbnails very often at all.

You also should not be "cleaning" Seren or any addon very often either. It's actually detrimental to metadata and artwork providers and slows your device down.

The OP states that he has no such issues playing from his NAS, so it's highly unlikely there is any kind of storage issue.

It could very well be the type of file he is trying to play or inconsistent speeds with his debrid provider, which upping the cache with advancedsettings.xml could get possibly help, if he hasn't already done so.

It could also be a number of other things. OP didn't provide a log or much else to go on, so it's just guesswork at this point.

Clearing an addon's cache isn't going to do a damn thing if his problem is during playback. Once the link is passed to Kodi's player, it's all on Kodi at that point. Sure the addon may still monitor other things in the background, but that is not going to cause the OP's issue.