I am trying to automate the process of "sending the screenshots of a monitoring tool dashboard to my WhatsApp number" at regular intervals.
IMO you're approaching this from a very difficult direction, far more than necessary. Sending screenshots of your monitoring dashboard is presumably so you can check and see when things break. But that's what alerting is for.
There are plenty of alerting tools, and if your monitoring db is a standard one then most of them will have hooks into it. The alerting software will run checks, and when the checks fail notify you by phone, slack, PagerDuty, whatever. This will be far easier to manage than a headless UI tool, will be something other future employees are more likely to have experience with, and most importantly, you won't get pager fatigue because it'll only be notifying you when things are wrong.