I suggest buying in bulk then. These work well in fabric baggies

Dry & Dry [6 LBS] Blue Premium Indicating Silica Gel Beads(Industry Standard 2-4 mm) - Reusable Desiccant Beads Silica Gel Desiccant https://smile.amazon.com/dp/B07QGX2MFQ/

Or

wisedry [ 5 LBS ] Silica Gel Beads Reusable Color Indicating Rechargeable Desiccant Bulk with 10 Pcs Organza Drawstring Bags https://smile.amazon.com/dp/B07QRRHJV3/

Comes with the baggies

Edit:

Also in case it’s not obvious. These aren’t magic. All they are doing is absorbing water and holding it until they are heated up again at which point they release it.

If you are drying them in the cabin you’re trying to reduce humidity in, and the oven vents to the inside of the cabin (more common in electric ovens, but I believe some lp ovens still vent some of the steam internally) you are keeping the humidity in a closed loop system. You need to dry these external to the system you’re trying to dry. (Be that an oven that vents outside or an oven outside of the cabin)

I suggest getting a weather station that shows humidity (can be had for $10-20) to see if you’re actually changing the humidity. Something like this

Govee Thermometer Hygrometer, Accurate Indoor Temperature Humidity Sensor with Notification Alert, LCD Bluetooth Temp Humidity Monitor with Data Storage for House Garage Greenhouse Wine Cellar https://smile.amazon.com/dp/B07Y36FWTT/

I’m running HA to show all the different sensors (PV/Energy/Battery a.s.o)

HA = Home Assistant?

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USB-C is somewhat a must. The Shelly temp sensors with batteries seem to be horrible and I don’t want to swap batteries once every few months…

The Shelly temp sensors are battery hungry because they're WiFi based. Zwave, Zigbee, or even BLE or 433MHz based sensors will last at least a year on a single set of batteries. I purchased some cheap Xiaomi LYWSD03MMC units over two years ago, and the CR2032 batteries are just now starting to need replacement.

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Any recommendations? I don’t have any smart home hub yet so I assume I need f.e. A zigbee hub in case I go for zigbee sensors?

Depends on which protocol you end up using. Aside from Zigbee, I've also used RF433 and BLE based sensors:

If you're already using Home Assistant, you can install ESPHome on any ESP32-based device and use it as a Bluetooth Proxy hub. I already had some ESP32 smartplugs and bulbs flashed with ESPHome, so it was as simple as adding a couple more lines of code to get a few BLE Proxy hubs, without needing to purchase any additional hardware for the hub(s).

Switchbot, Govee, ThermoPro, Inkbird, and Xiaomi all make fairly popular BLE-based temperature sensors.

Another option is an RTL-SDR antenna like this, paired with the RTL_433 add-on in HA. Then you can use any supported 433MHz sensors like this and this. 433MHz isn't a mesh network like Zigbee, but it does have longer range, doesn't require any pairing, and the sensors send updates every 16s, and take standard AA or AAA batteries.

This is what I use

https://www.amazon.com/Govee-Temperature-Humidity-Notification-Monitor/dp/B07Y36FWTT/ref=mp_s_a_1_2_sspa?adgrpid=118801713027&gclid=CjwKCAiAs8acBhA1EiwAgRFdw2GDL-sIw8A7Sbvib7Tj6yxAOXbZFhQT1WrjAOGv0RP5ufpjZd0DVxoCSwsQAvD_BwE&hvadid=489191294571&hvdev=m&hvlocphy=9033473&hvnetw=g&hvqmt=e&hvrand=12710678990116157132&hvtargid=kwd-1059615860060&hydadcr=5195_9612955&keywords=govee+smart+thermo+hygrometer&qid=1670539715&sr=8-2-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEzSEZCSllGQ1REVDM3JmVuY3J5cHRlZElkPUEwMjI4NjU3TU1LUzY1Nkg0UUlJJmVuY3J5cHRlZEFkSWQ9QTAyOTAzNDkzUTBGRTkwNEtINVZSJndpZGdldE5hbWU9c3BfcGhvbmVfc2VhcmNoX2F0ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=

I have this Govee Smart Hygrometer Thermometer.

Only $12, works great and has a bluetooth connection to your phone where you can track the temp and relative humidity. Pretty great IMHO.