Welcome to the Hubitat Community!
I'm in Toronto. Often look for warehouse deals on Amazon. I buy from the aforementioned sources too. However, do reach out to the community before purchasing specific device brands and types. Lots of good advice to be had here.
Some of the devices are challenging to keep stable, and some are very easy. Short answer, it depends. The TP-Link devices work locally with a very good community driver, so you can keep using those, but do yourself a favor and don't add too many WiFi devices. You'll regret it in the future.
Here are the officially compatible devices for Hubitat Elevation. You can find a device you're interested in and then cross check this list to see if it's there. If it's not, that doesn't mean you're dead in the water. There are lots of talented developers here that have written drivers and apps for devices that are not on that list. Just ask in the community if the search option in the forum doesn't pan out, but do search first.
Start with the docs and get familiar with how the interface works, learn about apps and drivers, and read the How to docs. Especially the docs about How to build a stable Zigbee and Z-Wave network. These technologies are different than WiFi and need to be setup and used in specific ways to get the best results from your devices and the hub.