All moving in the right direction which is good but don’t forget your little gadgets are measuring relative humidity rather than actual moisture content. The outdoor air may measure 99% relative humidity but could actually be a lot lower in actual moisture content so in your 10 c room you could be better off letting the window open to blow through the dry outside air. By example, our living room is about 19c with RH about 55%. The absolute humidity is 9grams/M2. Outside air is 10c 99%RH but absolute humidity is 6grams/M2, or 30% dryer in real terms.
I have a number of these little data loggers around the house and outside for collecting temperature and humidity both RH and absolute. Not expensive but very useful.