I think your best bet is to look into the Teams app store. That's how we came across our current performance management platform. We also try to run all our communication and collaboration through Teams so we were looking for a similar solution. The highest-rated option we found in the app store was Teamflect. We have been using it for a while and we are quite happy with it. I know they are Microsoft Partners as well so it really works inside Teams well. 

We currently use it for 360 reviews and recognitions. There are other tools in the app store as well so you can check them out as well. 

Give them a look and let me know if this has helped