@RandoIII 

The product itself isn't the problem, for me it's actually really good in the area I am in. 

Downgrading and upgrading the firmware failed due to a faulty component confirmed by TP-Link UK R&D and Support teams. 

I have had multiple remote sessions with them they have tried importing a new firmware by way of SSH, TFTP and other methods that haven't worked so luckily for me the unit is under warranty and has been rma'd.

Luckily some of the community solutions worked to some degree for me but then failed the firmware flash. The Deco lineup really isn't that bad just depends on what the use cases are, for me I am in a broadband deadspot so mobile data is my only option other brands like the Huawei 5G doesn't gain enough of a mobile signal to remain connect but Deco X50-5G has been stable on mobile data just remains a security risk being on an outdated firmware. 

  @Bar666xp 

This was confirmed to be a defective unit after TP-LINK contacted me to run some testing. 

They spent approximately a week gathering data from the old unit and running update tests one after the other to check which firmware would work and which didn't. 

The unit was marked as defective and RMA'd I have had a replacement now so I couldn't tell you for what the issues were or how it was caused. I am just going off of what I have seen, tested and tried myself and what I have seen TP-LINK's agents had tested.

Overall, I downloaded the firmware from the UK site, I purchased the unit from Amazon UK so theoretically the UK Firmware should have been enough but it appears to have only worked with the factory supplied firmware (I can't remember the Version Number) Since receiving the replacement, this has auto updated itself without an issue which the first unit failed to do. 

Sucks really, I am out in the sticks no physical broadband service here so Mobile Data is all I have other models like the HUAWEI H122-373 5G or the ZTE G5B 5G just didn't perform as well as this. I even have the Extension Antenna's on the roof for further coverage and this TP-Link out performs any other on stability, signal strength and Wi-Fi through-out. 

  @Quantum1965 

The issue I had was a defect on the RAM Chip, I had to put in an RMA to get this resolved. 

I had TP-Link QA Support Staff Remotely logging into my laptop to attempt all many of fixes but low and behold the unit was still defective. 

After the RMA, I was informed that the unit had a defective RAM Module (Wasn't told specifics) that was causing the update to appear to be successful then reverted back to the default firmware that it was shipped with. 
 

I would recommend following the steps. 

Go to TP-Link My Products
(Besure to select your region on the login screen top right) 

Login with your Community details 
and log an RMA Request. 

If the unit is defective then a replacement is your best option. Mine has been fine since