WD My Cloud Home 4TB issues..Is it about to fail?

Hi all,
I bought a my cloud home 4tb about 18 months ago, bought it to use for mass storage and to use as a plex server and it has been flawless up until now. I have had to reboot and disable and re-enable plex a few times but thats technology and these things happen.
However a few days ago, after not using plex for about 2 weeks, I went on to plex to find connection unavailable on my cloud server, but I also have a plex server on my computer that can use the library on the my cloud and I was able to access via that, but the files took a long time to load and constant buffering during playback. So I checked my internet connection and it was ping 8 D/L 208 Mbs so no problem there, tried 3 different ethernet cables with no improvement so can rule that out.
Next I checked on file explorer and wd discovery and it was showing ok and can access files and folders but very slow, tried to play a video file from the drive on the computer and also very buffery and same result by playing via mycloud home website. At this point the mycloud home had been running constantly, so I shut down via mycloud home website interface unplugged and thought to power back up the next morning, after disabling the plex server and removing it from the plex web app with the intention of re-enabling it and reclaiming the server after powering back up.
The next morning I powered the my cloud back up, but it took around 20 mins of what wd calls slow breathing before settling back down to a solid white light. WD discovery picked it up and I was ans still can view all files on the desktop and on the wd mycloud site but again painfully slow for each folder to load up. I went re-enable the plex server but it just kept coming back to the enable button, a further re-boot(much quicker this time) and when I went back to the enable plex screen it was showing as enabled, great, so clicked on configure and got the using plex screen, then after clicking on next all I get is either internal server error or “Page isn’t working. Currently unable to handle this Request. HTTP ERROR 502”
So now im panicing because a lot of those video files are unable to be replaced, but as I can still access them I thought I would see if I can copy them onto another drive, I selected 1 340mb file to test however it was painfully slow, windows calculated 35 mins to copy a 340mb avi file. I’m stuck as to what to do next, can anyone help??
Sorry for the long post just wanted to give the complete story
FACTS AS OF 2.30AM (BRITISH TIME) 23/11/2020
THE MY CLOUD HOME BOOTS UP OK, EVEN IF SLOWLY
BOTH MY CLOUD DISCOVERY AND MY CLOUD SITE RECOGNISE THE DRIVE
I AM ABLE TO ACCESS FILES AND FOLDERS
SETTINGS SHOW CONNECTION AS LOCAL, BUT ON SOME REBOOTS IT CHANGES TO RELAY
PLEX SERVER WILL ENABLE BUT TAKES UP TO 7/8 ATTEMPTS, BUT WILL NOT MOVE BEYOND USING PLEX PAGE
ATTEMPTED FILE TRANSFERS ARE VERY VERY SLOW, OR EVEN GET HALF WAY THROUGH AND THEN FAIL WITH CANNOT READ FROM DISK(ONLY HAPPENED ONCE)
WD MY CLOUD HOME 4TB
WINDOWS 10 HOME
VIRGIN MEDIA CABLE 200MB CONECTION-3 DEVICES CONNECTED VIA ETHERNET

Please help, is the drive about to fail and how best can i rescue things???

Quick update, still cannot configure plex, but can still boot up my cloud home with no problems plus see all files and folders.
have done a ping test via virgin hub, comes back as no packet loss, repeated test 4 times all no packet loss