Mousepositions/clicks on diff. screen resolutions

[Rainroom69]

Following situation:
KW = wapcontact1
command = https://wa.me/+XXxxxxxxx?text=$U$$W2$||setmousepos 642,448||mouseclick 642,448
(XXxxxx = tel. nr)

The getmousepos (not decribed here) is used to identify the Whatsapp button position of the 'continue to whatsppweb' (some splash screen).

The KW is used to send a whatapp message to a 'contact1' with the purpose to directly be able to write on as the contact is found in Whatsapp web.
The problem is when other screen resolutions are in scope. Ex. when laptop is connected to docking station with other bigger screens. The mouse position is I think diff... and therefore it doesn't work.
How to get this 'dynamic' so there is no need to change the 'values' each time, which is not workable....?
What's the steps exactly to get this done ? Know there's a lot of tweaking possible with perentages etc.. but don't get it to work.
Most likely I try to make it too complicated. Any suggestions pls ? Thanks.