Query against Visa exit and NOC

Hello sir/Ma'am,
My kind request If you could help me with your answers to below queries regarding visa and NOC during my exit from Oman.
- I'm an Indian expat, working in muscat. My visa is going to end on 25th July 2021.  I have already shared my resignation with my manager and they have processed and accepted it.
1. How can I cancel my visa during the exit, as I heard from some of my fellow colleagues that nowadays the PRO doesn't come to airport to cancel our visa, but they will do it on their own through the company without visit to airport. Is it true ? Can they can my visa like that ? Has the rules changed now ? Don't they need to come to visa cancellation counter along us to cancel it ? .
2. What all documents do I need to ask from my company as I'm resigning from here and that will be required for me in my career future.
3. Can I travel for employment to any other GCC country say qatar or Kuwait or Dubai after my exit in Oman. How will I come to know if my employer has cancelled my employment visa or not ?
4. Do I need to ask my employer to provide a NOC even if I'm exiting the country by cancelling my employment visa ?
5. I also have a very minute elevations in my bilirubin levels, which I came to know during my last gamca medicals during 2018. initially they dint agree to provide me a fit certificate and asked to provide a retest after few days. But simultaneously I had checked it with other doctors and they told that it was not a concern at all and it's completely normal for me to have a little high values. Even I have been checking for past two years and they appear to be in same range. I'm worried for my current visa medical in gamca, if the values tend to appear in the same range then will they provide me a unfit certificate ? How can I convince them?
6. I have a landline omantel wifi one year contract plan. Actually it's registered on my name but I and three of my friends share the wifi. I have the wifi contract untill November 2021. So I wanted to know how can I cancel my contract with omantel, as they tell that if i do so they will apply penalty charges of 90 rials. How can I skip these charges to cancel it or can I transfer the ownership to any of my friends name as they will be using it even after I leave the country.