[Samsung Galaxy Watch 4] TheMystic:
During this week, I was playing around with my Watch4, and this post is about some of my observations, and conclusions about the same. Please feel free to correct me if I am wrong with any of them.

There are essentially two categories of 3rd party watch faces:

1. CATEGORY 1: One that uses resources within the watch itself to display information.

The Android phone app for this category of watch faces merely send the store link to the watch face so you can simply install the app from the watch itself. The Android app here has no further role and can be uninstalled from the phone. But I would recommend that they remain installed in the phone because of a specific benefit: you can quickly install these watch faces from the watch because all these appear under 'Apps in Phone' section of Google Play Store app in the watch. So instead of uninstalling, it is better to put them in deep sleep (optimised state) on the phone.

Some of the watch faces in this category are:

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01. amoledwatchfaces​

02. HMKwatch (or HMKwatch)​

03. Matteo Dini MD​

04. Ballozi​

05. Bosenko East (or Bosenko)​

06. fatih sendur​

07. WFProduction by A.Kovalev​

08. PERSONA Watch Face​

09. WINwatchface​

10. Tancha Watch Faces​

11. Yosash​

12. Chester​

13. Ntv Watchfaces​

14. Active Design Watch Faces​

15. Lihtnes​

16. SMZ JeonDaeHyun​

17. MDS​

18. Digital Wings [DW]​

19. SHIFR​

20. EK​

21. IV Watch Faces​

22. Timeflik (ex Mr. Time)​

23. MyWF Cartel​

24. Inspire Watch​

25. Prado Design​

26. MW Design​

27. Re: Brand​

28. Amser Watch Faces​

29. MW Design​

30. MatveyAn​

31. MDS Watch Faces​

32. styles4you​

33. Inspire​

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and others.​

All the above watch faces are either paid or have in-app purchases. They don't come with an accompanying Android phone app for their working, with very few exceptions that need the Android app just for phone battery feature.

2. CATEGORY 2: One where the watch face connects to its companion app on the phone over bluetooth/ wifi/ nearby devices to exchange information. In this case, the companion apps on the phone must keep running in the background in order to update certain information on the watch. e.g. phone battery level, etc.

The Android phone apps for this category of watch faces usually come with ads. although there are exceptions. For these apps, I have seen that almost every feature/ customization for these apps are locked behind a paywall. Personally, I find most of them very annoying, although there are exceptions. The following are some of the developers who engage in such a practice:

No ads; only in-app purchase

1. SOOON​

2. GS Watchfaces​

Ad supported; in-app purchases to unlock most features and customizations

1. RichFace​

2. thema​

3. Smart Art Studios​

4. DeNitE Appz​

​

and others.​

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The problem that I have noted with this Category 2 type of watch faces is that they may interfere with the connection between the phone and the watch. This is only an observation and I may be wrong. So the community can confirm or reject this observation.

In my case, the Galaxy Wear app as well as Smart Things app were having too much problems in displaying the battery level of the watch when I had this 2nd category of watch faces installed. Once I uninstalled all these, the problem seems to have been sorted. I must mention here that I had put all these companion apps in deep sleep mode on my Samsung phone. My guess as to why this created problems is because the watch faces were trying to contact their companion apps, which were not responding as they were optimized. This probably led to the connection being overwhelmed by these watch faces that resulted in the problem noted above.

UPDATE: My suspicion is probably correct. Apps and watch faces that REQUIRE a companion app on the phone are indeed the most likely culprit for this problem. The solution is to disable battery optimisation for these apps on the phone, or uninstall such apps from both the phone and the watch.​

ADDITIONAL COMPLICATIONS SUPPORT

The following apps will add support for corresponding complications for all your watch faces that support WearOS/ 3rd party complications (i.e. those that are not designed to get complications only from their own companion apps on the phone, e.g Manager by SOOON):

1. Phone Battery Complication

2. Complications Suite - Wear OS

3. Heart Rate Complication

4. Health Services Complications

5. SimpleWeather

6. SimpleWear

If you have any of the above apps installed, you'll be able to add the corresponding complication to all of your watch faces. For example, if you add the 2nd item above, you'll be able to add UTC Time, day number, week number, etc. to all your watch faces, even if they don't come with it. Same holds true of BP, and other health related complications.

RELATED POSTS

You'll find more info and related links here:

https://xdaforums.com/t/wear-os-facts.4462733/