On some templates i find it impossible to change the colour of the header and the H1 from the pagetitle (from the menu-item) Where i can change this in many other templates  i can not get this done on for example the template hifi, modern and perfect. So what do i wrong in this. Not even chat gpt can get it done for me even i show him the sourcecodes. So i hope you can help me with the solution

Which support employee said that? Here in the JP forum? All templates are structured the same and programmed identically. If it works on other sites, then these are individual problems, or did you install both templates on sites where there are no problems and find that it doesn't work there either? Without links to the affected sites, it's impossible to provide proper assistance.

take a look at de-solcers.nl
it is template Modern
i change the colour of the header in #4667BB
but when i save it the colour is 575EB7 (colourpicker) the given colourcode is the code i give in but after saving you see another colour.

Super User Login please (use lock symbol).

Make a backup beforehand.
 

you mean i give the admin login codes

yes