I’d like to add temperature sensing (for a few freezers to make sure they stay frozen) as well as ambient temperature sensing for around and outside my house.
There are three options that I’m considering and I’m hoping the community can assist with pros and cons of each:
Ideally I’d like something that integrates reliably with HA with a minimum of fiddling.
If you don’t mind a cloud-based solution, you might check out YoLink Amazon.com
I put the temperature sensors in my fridge and freezer and they’ve been working great.
There are a couple good Ecowitt integrations with HA that are local only, so you don’t have to have any kind of external account or connection. I used a number of those around my house (433mhz radio sensors with a Ecowitt wifi bridge). They’re really good if you’ve got spots with spotty network connectivity.
I recently switched everything over to ESPHome devices with various sensors, mostly as a hobby project thing, not because the Ecowitt’s weren’t working.
I’ve had very good luck with several brands of Bluetooth BLE temperature sensors in fridge and freezers. Unfortunately, my best performing devices are Goove AAA bettery powered units that they no longer sell. The AAA or AA battery solutions seem better in low temp environments than the Lithium battery based devices, mostly battery life. My AAA powered units go 1 + years in freezer.
Have a look at these two devices, as both have Home Assistant integrations and are designed for long range, which seems to equate to powering thru a freezer metal wall or frozen tomahawk ribeye 
Good hunting!
For outdoor weather sensors I use Ecowitt. It’s a little fiddly to set up (you need the wifi gateway as well the various sensors) but it’s local, there’s a HA integration and mine has been running with no attention whatsoever for nearly a year.
For fridge temperatures (and elsewhere in the house) I’ve been using Wireless Sensor Tags for several years. These are cloud based and the integration is still yaml, but they are very versatile (humidity as well as temperature, and you can stick them on doors to detect movement).
There may be issues with battery life for anything you put in the freezer, and in the fridge or freezer you have to watch out for condensation if the sensor is not permanently sealed - wireless tags have to be in a ziploc bag. I have also read that zigbee may not perform well in a fridge or freezer because the signal is very low powered.
Here is a link so some research I did a while ago, probably still a useful guide. In my original post, I should have also said, that I use exclusively BLE temperature and humidity through inside and outside house with very good experience with Home Assistant. Nothing based on Zigbee or WiFi has be able to come close to the BLE devices on any dimension.