I feel sorry for you. I do not understand why you would keep that much money in Metamask when you had other options that were not browser based but you should accept the funds are probably never going to be returned and you have move forward with your life you cannot be thinking about it all the time. Also, you have to use this event as a learning process therefore try to go through the events leading up to the hack, maybe you will discover how the funds were stolen.

The first thing you have to consider is using anti-malware software with deep clean and analysing then study the results because your device could still potentially be compromised.

This has to be good advice, I hope the OP manages to accept this had to be some form of security lapse or failure on his part and once he ascertains what happened he will not repeat the same mistake.