[Wear OS Q&A, Help & Troubleshooting] underlines:
installed com.android.vending_17.3.27 (Google Play Store) apk via adb

installed com.google.android.gms_19.6.29 (Google Play Services) apk via adb

but logcat still spits errors out, like something's missing or blocked:

11-30 22:52:51.827 1661 1675 W BroadcastQueue: Background execution not allowed: receiving Intent { act=android.os.UpdateLock.UPDATE_LOCK_CHANGED flg=0x4000010 (has extras) } to com.google.android.gms/.chimera.GmsIntentOperationService$PersistentTrustedReceiver
11-30 22:52:52.141 6106 6106 W Finsky : [2] dig.a(6): Null bundle, which breaks event chain!. Creating a new logging context.
11-30 22:52:52.203 6106 6114 W System : A resource failed to call end.
11-30 22:52:52.204 6106 6114 W System : A resource failed to call end.
11-30 22:52:52.223 6106 6106 E AndroidRuntime: FATAL EXCEPTION: main
11-30 22:52:52.223 6106 6106 E AndroidRuntime: Process: com.android.vending, PID: 6106
11-30 22:52:52.223 6106 6106 E AndroidRuntime: java.lang.RuntimeException: Unable to start activity ComponentInfo{com.android.vending/com.google.android.finsky.wear.activities.MainActivity}: android.content.ActivityNotFoundException: Unable to find explicit activity class {com.android.vending/cwc}; have you declared this activity in your AndroidManifest.xml?
11-30 22:52:52.223 6106 6106 E AndroidRuntime: at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2914)
11-30 22:52:52.223 6106 6106 E AndroidRuntime: at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3049)
11-30 22:52:52.223 6106 6106 E AndroidRuntime: at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78)
11-30 22:52:52.223 6106 6106 E AndroidRuntime: at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108)
11-30 22:52:52.223 6106 6106 E AndroidRuntime: at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68)
11-30 22:52:52.223 6106 6106 E AndroidRuntime: at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1809)
11-30 22:52:52.223 6106 6106 E AndroidRuntime: at android.os.Handler.dispatchMessage(Handler.java:106)
11-30 22:52:52.223 6106 6106 E AndroidRuntime: at android.os.Looper.loop(Looper.java:193)
11-30 22:52:52.223 6106 6106 E AndroidRuntime: at android.app.ActivityThread.main(ActivityThread.java:6680)
11-30 22:52:52.223 6106 6106 E AndroidRuntime: at java.lang.reflect.Method.invoke(Native Method)
11-30 22:52:52.223 6106 6106 E AndroidRuntime: at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
11-30 22:52:52.223 6106 6106 E AndroidRuntime: at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
11-30 22:52:52.223 6106 6106 E AndroidRuntime: Caused by: android.content.ActivityNotFoundException: Unable to find explicit activity class {com.android.vending/cwc}; have you declared this activity in your AndroidManifest.xml?
11-30 22:52:52.223 6106 6106 E AndroidRuntime: at android.app.Instrumentation.checkStartActivityResult(Instrumentation.java:2005)
11-30 22:52:52.223 6106 6106 E AndroidRuntime: at android.app.Instrumentation.execStartActivity(Instrumentation.java:1673)
11-30 22:52:52.223 6106 6106 E AndroidRuntime: at android.app.Activity.startActivityForResult(Activity.java:4587)
11-30 22:52:52.223 6106 6106 E AndroidRuntime: at eo.startActivityForResult(PG:4)
11-30 22:52:52.223 6106 6106 E AndroidRuntime: at android.app.Activity.startActivityForResult(Activity.java:4545)
11-30 22:52:52.223 6106 6106 E AndroidRuntime: at eo.startActivityForResult(PG:2)
11-30 22:52:52.223 6106 6106 E AndroidRuntime: at android.app.Activity.startActivity(Activity.java:4906)
11-30 22:52:52.223 6106 6106 E AndroidRuntime: at android.app.Activity.startActivity(Activity.java:4874)
11-30 22:52:52.223 6106 6106 E AndroidRuntime: at ewx.b(PG:35)
11-30 22:52:52.223 6106 6106 E AndroidRuntime: at ewx.a(PG:19)
11-30 22:52:52.223 6106 6106 E AndroidRuntime: at com.google.android.finsky.wear.activities.MainActivity.a(PG:5)
11-30 22:52:52.223 6106 6106 E AndroidRuntime: at ewx.onCreate(PG:6)
11-30 22:52:52.223 6106 6106 E AndroidRuntime: at android.app.Activity.performCreate(Activity.java:7144)
11-30 22:52:52.223 6106 6106 E AndroidRuntime: at android.app.Activity.performCreate(Activity.java:7135)
11-30 22:52:52.223 6106 6106 E AndroidRuntime: at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1271)
11-30 22:52:52.223 6106 6106 E AndroidRuntime: at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2894)
11-30 22:52:52.223 6106 6106 E AndroidRuntime: ... 11 more
11-30 22:52:52.226 6106 6106 W Finsky.CrashDetector: Crash at version: 17.3.27-all [5] [PR] 278037957 cnt=4 ts=1575128953673 cause=RuntimeException fg=false".
11-30 22:52:52.238 1661 1944 W ActivityManager: Force finishing activity com.android.vending/com.google.android.finsky.wear.activities.MainActivity
11-30 22:52:52.342 1661 1675 W BroadcastQueue: Background execution not allowed: receiving Intent { act=android.intent.action.DROPBOX_ENTRY_ADDED flg=0x10 (has extras) } to com.google.android.gms/.stats.service.DropBoxEntryAddedReceiver
11-30 22:52:52.343 1661 1675 W BroadcastQueue: Background execution not allowed: receiving Intent { act=android.intent.action.DROPBOX_ENTRY_ADDED flg=0x10 (has extras) } to com.google.android.gms/.chimera.GmsIntentOperationService$PersistentTrustedReceiver
11-30 22:52:52.545 1661 3363 W ActivityManager: Scheduling restart of crashed service com.android.vending/com.google.android.finsky.scheduler.JobSchedulerEngine$PhoneskyJobSchedulerJobService in 1000ms