I had an Ender 3 S1 plus until 3 months ago and didn’t really have many problems with print quality. I now have the K2 plus with cfs. With the Ender the reel was often left on the machine for a week or two. When I first started using the reels on the K2 I often had troubles and even drying for hours didn’t help much. Since then I have moved to hyper PLA on plastic although it seems only cardboard reels are becoming available. I changed the dessicant in the cfs using reusable bags but never got Rh readings below 30%. Saw a video from a guy who advocated loose orange/green beads. Even had a pair of trays to print for the cfs. So I bought some and printed the trays. Humidity stays around 16-18% now and stringing and so are no longer a problem. Thinking about it the bags have 2 layers of protection against getting at the moisture from the cfs but the beads only have 1 so maybe that makes a difference.
I completely agree with you on this. I also want to point out how bad deformed cardboard spools are for printing. I bought some from amazon, not too long ago. The filament was great, but the spools were a little smashed in transit. These spools cause issues in my AMS 2 PRO.
I think the best move to make is purchasing refills off Amazon (the rolls that come without the spool) and putting them into the reusable plastic spools. The annoying thing is that, depending on what colors you need, or the brand you prefer, the reusable spools are all different sizes). have 6 unused reusable spools because of this.
If anyone has a great solution to this, I would be interested to hear about it.
Regarding your drying issue, do you use silica packets in your filament dryer?