I'll also add autobrr as a great way to automatically download from IRC feeds too if your sub groups of choice have IRC channels. I've found that it can grab faster than RSS.

https://github.com/autobrr/autobrr

I've used these in a drybox to keep filament dry, and they work really well for that, but to actually dry filament I use what amounts to a modified food dehydrator. You really need heat and airflow to get moisture out of already wet filament. If you don't have a food dehydrator you can use, you can also try an oven, but be careful of temperature fluctuations which could cause it to get too hot and melt your filament.