General Problems with Plex

I have listed my hardware and software configuration below, alongside the issues and questions I am facing.

The following problems occur when using the Plex Media Server:
• When “Network” > “NAS” is selected as the source on the TV set, various selection options for movies appear—e.g., “All Movies,” “Recently Added,” “Release Year,” etc. A “spinning circle” then appears, and eventually—after several minutes—the message “No playable files…” is displayed.
• Neither on the computer nor on the TV do videos I filmed myself and edited using Magix VDL 2025 (MP4 format) appear within Plex (see versions listed above), even though they are listed in Windows Explorer on the NAS under “Shared Videos.”
• Videos and photos deleted via the PMS continue to appear in the PMS poster view on the computer, marked with a trash can icon; I have repeatedly run the “Troubleshooting” option within the PMS menu to no avail.
Questions:

  1. Which Plex applications should/must be installed on the various hardware devices? (Plex Home, Plex Web, PMS, Plex TV, etc.?)
    In this regard: My primary intention is to use the NAS—either alone or in conjunction with the TV—solely to watch my own home videos, as well as a few feature films and other media stored on the NAS, directly on the TV! The Plex library structure is, of course, well-suited for this purpose, but unfortunately, I am currently unable to utilize it as intended. I have no need—at least for the time being—to stream TV channels, share libraries with friends, or use similar features!
  2. Which connection method between the NAS and the TV is the most functional and optimal? Should I access the media via the TV’s “Network” source option, or via the PMS application installed directly on the TV? Even a very thorough support session with Western Digital failed to resolve this specific issue, though I am able to contact their support team again at any time. When I select Apps > Plex on my TV, I see a screen interface that looks like this:
    Which Plex program is this? Why is the graphical interface displayed here completely different?
  3. Is there—without a Plex Pass—any restriction regarding the number and/or total size of videos in the media libraries, or regarding their structure? By way of explanation: I created a movie library titled “My Own Movies” to “separate” my home videos from other content—e.g., feature films, TV shows, etc. In total, there are now approximately 2,000 videos/films, in various formats (mp4, avi, mts, mkv, etc.).
  4. Despite running the “Troubleshooting” tool in PMS, posters that were deleted (some quite a while ago) are still being displayed with a trash can icon?

Hardware & Software Configuration
Fritz!Box: AVM 7490
Computer: Asus Vivobook 13th Gen Intel(R) Core™ i7-1355U (1.70 GHz)
RAM: 24.0 GB;
Graphics Card: Intel(R) Iris(R) Xe Graphics (128 MB)
Windows 11 Pro
Connected to the network via Wi-Fi;
Plex for Windows installed: Version 1.112.0.359-0d79a49f
NAS: WDMyCloudMirror, 2-Bay Personal Cloud Storage; Firmware 5.33.102
Connected to the network via LAN
Plex Media Server: Version 1.43.1.10611
. Power schedule enabled daily from 04:00 – 06:00
TV: PHILIPS 480OLED806
Connected to the network via Wi-Fi;
Plex (?) 10.30.8.4222 (58d01a81)

Mein Posting habe ich mit Google Translate aus Deutsch in Englisch übersetzt. Vielleicht sind deshalb manche begriffe nicht korrekt.

Ich würde mich über Antworten in Deutsch (von deutschen Usern?) freuen.