On newer Canon cameras (such as the 200D that I own) there is no longer the option to use the IR remote. Instead you have to buy a special Bluetooth remote (the Canon BR-E1) that costs $50 and is quite bulky.
Is it possible to replace it with a mobile app somehow? I know there's an official app to control the camera through Live View, but it's quite slow and only works in Wi-Fi mode.
The latest version of Camera Connect App have a "Bluetooth remote controller" function, doing the same as BR-E1. It doesn't support all cameras - i.e. it doesn't work for Canon 77D, but does work for the R8.
Just because there is no IR port does not mean the camera can not be remotely controlled other than by Bluetooth. The camera also has the more traditional port for a wired remote.
In the case of the 200D the wired shutter release port is a 2.5mm mini stereo jack which allows a simple three way switch (off/half press/full press) to operate the camera's shutter remotely.
Since wired remotes are incredibly simple and almost universal in the way they operate (the only difference between those made for the vast majority of different cameras are the shape of the connectors), there are a plethora of accessories available to use the wired remote port as a wireless radio trigger.
If you're close enough to use a wired connection, many remotes are both very affordable and fairly compact. This one is currently $8 USD at amazon.com:
If you want a greater range than a wired cable allows, there are radio triggers that use the wired shutter release port to interface with the camera. This one operates in the 2.4GHz band and has a range of approximately 80 meters. It's also fairly compact and affordable.
If you're really dedicated to using WiFi there's always DIY on the cheap.
