I started with a Google Mini and added the Smartthings 2018 hub and thought that took care of everything. Google home and Smartthings. Then IFTT got connected and now IFTT says it works better with Smart Life , so I might add that, and I bought a Globe light so I think I’ll be adding Globe and or Tuya to it all…
I’m still a newbie but before I go adding all these together to work with Smartthings or google or IFTTT I want to check in with the community and see if I’m going to regret this or if I’m missing something?
Sometimes I think "just add everything to ensure everything can work with everything in an optimal manner… That’s when I snap out of it and realize I need to ask you guys.
Privacy must be a risk…
But could I lose functions with Smartthings by adding these other apps?
You won’t lose any functions. Honestly, it’s just a matter of taste as to whether or not it bugs you to have multiple apps.
Again, the first rule of home automation applies: “the model number matters.“ 
In some cases, you’ll only need the app to set up the device initially.
There will be others that you will use to set up automations that run, well, automatically, so unless you’re creating a new rule, you won’t need to worry about them.
At our house, we mostly interact with the home automation system either through schedules, sensorbased rules, or a voice assistant, so we don’t need the apps on an everyday basis.
But if you’re the kind of person who is going to be pulling out your phone and using the app all the time, then you may want to limit yourself to an app which can handle most of your devices.
So it just comes down to the details of how you yourself will use it. But you won’t be losing functionality just because you have multiple apps on your phone. 
I have 24 home automation apps on this iPad, and another dozen or so on my phone. But there’s only one that I use on a daily basis. All the others are hidden away in a “home automation“ folder for when I need them. Which isn’t often.
If you want to have one place to control your devices, they have to be inside one app. And if you want your devices to be able to “talk” to each other, they have to be interconnected. So, having a bunch of stuff paired to different things gives you remote control but doesn’t provide a truly automated solution.
SmartThings is my central Hub. I have many other “Smart” devices that could be used as standalone in their own apps but I like to populate everything I can into the ST’s App.
For example: I have Ecobee therms, Blink and Amcrest cameras, Ring Doorbells, Alexa devices, Harmony Hubs, Hubitat Hub, Magic Home leds and others. All of these are better viewed and configured in their own apps. But I can still use ST to automate them when needed.
Even with Hubitat, I use ST as the main viewing platform. Just makes things easier when troubleshooting. For most things, ST and webCoRE does the trick. However, there are situations where an Alexa routine or Harmony Activity or Ecobee schedule is way more intuitive just using that particular Smart Device’s own App.
The devices he is talking about, SmartLife, Tuya…they don’t allow you to connect to ST and their own cloud servers at the same time.
That’s how I understood it. This is the same as Blink Cameras but they can still be connected to ST via IFTTT. This is what I’m assuming the OP will do as well.
The “downside” of not having direct integration is relying on a “middle-man” service which puts another variable in the equation of “what could go wrong”.
I guess I was really saying that although I have “things” connected to ST doesn’t mean that ST is the best “App” for configuring those things. But ST is great for adding automations especially if you want to use webCoRE and it’s robust rule engine.