I ordered these and they have been excellent:
https://www.amazon.ca/gp/product/B07...GFW0OQJA&psc=1
Price fluctuates between $7.99 and $10 day to day and when the 2-pack is available it's $14.99.
32GB gives you approximately 4 days of loop footage - it will automatically record over the oldest footage when full, and still records all events in the cloud just like it does without a micro SD card.
The cards are a little tricky to push in the bottom of the camera and it's spring loaded, so just make sure it's in all the way. Format the card in the camera (option to do this in the app) before first use.
The bitrate is ~100KB/s so you don't need anything fancy at all in terms of memory card.
For the price, there really is no reason not to pop a mSD card in there to guarantee no gaps in footage. You can view it all from the app too, it's great. It even marks the events on the timeline.