Okay... based on what I can determine from the photos I think there's a dual issue at work here.
The Magenta cartridge in use probably has a build up of pigment sludge on the internal filter mesh that sits above the outlet sponge and this is restricting ink flow.
Given that the use of OEM...
Thought I'd just record this error and the fix we worked out today on a Canon iP8750.
Printheads was moving back and forth fine but the printhead would stop about a little out from the right side with error flashes and an error code of 6A81.
The error normally indicates some kind of paper jam...
So, it's likely, on balance, that the newer service tool is the one to get so long as it's a genuine release and not someone getting cute with malware...
The bit you @PeterBJ, mentioned about changing the hardware seems to be key to keeping it functioning though. Any change and the app won't...
If you have some old refillable cartridges those use the 4mm plugs you need. I'm guessing you're in the US given the imperial measurement or I'd say I've got them on OctoInkjet too.
*dusts off account and taps the mic'*...
"Hello? ... Hello?... Is this thing on?..."
Yes, dear folks I have returned from fighting demons**, climbing great heights and smiting the evil doers who brought us Brexit and Aunt Bessies frozen yorkshire puddings (Heretics all!) and I seek your help...
Well, he could ... just sharing that 7zip is a really useful utility for decompressing a lot of different compression file formats...
Winzip is the devil incarnate though... Evil, nasty developerssssss. We hatez them don't we preccioussss ;)
Could be a few things... I'm busy finishing a video that's aimed specifically at troubleshooting Ecotank printers but due to technical issues I need to reshoot some of the footage and then edit the whole thing so it's going to be a week or so before it's done but don't throw the printer out just...
Oof! If it was second hand and I'm guessing has had some moving around it may have had ink or similar that shorted out some of the electronics. That's gotta hurt though. Hope it wasn't too expensive.
Actually just checked and the WICReset app also supports the TS5000 series so it should be able to do what you need as an alternative to the Canon service tool. You'll need to purchase a WICReset key though.
The instructions @PeterBJ provided for getting it into service mode still apply though.
FWIW: if you can get hold of older firmware updates that don't have the third party crippling function you can extra the necessary file to a memory stick and use that to revert your firmware to an older version.
https://support.printerpotty.com/2022/hp-firmware-downgrade
As waste ink is my bag I can tell you that your caution is well advised... The ET-8550 is supported for it's main waste ink output by the maintenance box that you can change out yourself... BUT, the platen waste ink pad (and counter) are locked away from the end-user and cannot be reset.
Now...