I have read the few posts regarding the door side protectors but I am coming from a slightly different angle.
Have today picked up a replacement bare door from a salvage yard in the correct colour so I went for it. Problem is it has the door side protection strip on it whereas the others do not. Have read is fairly easy to remove old strip as only stuck. Can anyone say if this is true? If it is hard to remove I may now have the problem of getting strips to fit the other 3 doors.

The side protection strips are held on with 2 parallel, upper and lower strips of 3M tape.
Yes they are removable, be careful not to damage the lacquer, use a mild heat gun or hair dryer to soften the glue.

Use this video to see what they are and how they fix.

Can you not get a set, and just fit the other 3? Just a thought. Hyundai Ioniq 5 Ultimate. The family car.
2009 Rimini Red SE TD4. Gone.
2006 Tonga Green i6 HSE. Gone.
Audi A5 convertible, my daily driver.
1972 Hillman Avenger GT, the project.

Lighter fuel (as in Australia https://www.bunnings.com.au/diggers-1l-shellite_p1563463 ) will clean up any sticky residue.

Then get 4 new ones!

& 4 window wind deflectors while at it. Procrastination, mankind's greatest labour saving device!

Acoustic insulation ARB TPMS 3xARB air compressors After cooler Air tank On-board OCD pressure air/water cleaning Additional 50L fuel Carpet in doors ABE 2x1kg Waeco 28L modified fridge Battery 4x26ah Solar 120w Victron MPPT 100/20 DC-DC 18amps 175amp jumper plug Awning 6x255/60R18

I will first try to remove the one on the door first. If it does not look to nice will get a new set.
Already have the deflectors.

Well got old trim off no problem. Got most of residue off also but would appear that the bits stuck on really well will not come off , I tried petrol no luck. Also appears to in places remove lacquer and paint leaving primer showing so have ordered a set of protectors anyway.