Dulux Tranquil Retreat is a popular choice.

Is there anything wrong with the current sandy paint , condition-wise ?

I'd be tempted to keep it , double down with the dark highlights -- do the gutters , the downpipes , that 'upstairs' barge board etc in charcoal to match the windows . and spend any savings on the gardens , maybe even a dark stained timber deck in front of the glass entrance doors .

And on that note -- is that what you want to replace with a wooden door ? It will be dark ( even if you have glass down each side , doubly so if you do a double wooden door ) and while it won't be horrible , one bit of wood with a mainly grey or sand colour scheme , and charcoal frames everywhere , isn't all that cohesive and matching IMO .

The current colour is horrible in person, it’s also done terribly and in spots you can see the colour the house used to be before previous owners painted it. the old roof was the same colour as the house as well.

The glass sliding door will eventually be replaced with normal timber doors but painted black.

Window frames will either stay black or be painted white. Fascia boards will probably go black (or dark dark grey), white or basalt like the roof.