Sicily Sardinia and Malta

The answer is "NO!'

Two weeks for Sicily alone.

I'd say pick one. We spent a month+ in Sicily and it wasn't nearly enough. You also could spend two weeks in Malta. Check out dlinstrom's trip report on Sardinia. More than one wouldn't do justice to any of them.

It would be fairly exhaustive for Malta, but on Sicily and Sardinia you would barely scratch the surface plus lose transit time.

I think trying to fit all 3 into just two weeks would be a bit too much—you’d spend a lot of your time in transit. I’d recommend narrowing it down to either:

Sardinia and Sicily – one week in each. You can travel from Rome to either island by flight, then take the ferry from Cagliari (Sardinia) to Palermo (Sicily):
https://www.ferryhopper.com/en/ferry-routes/direct/cagliari-palermo

OR

Sicily and Malta – maybe 10 days in Sicily and 3–4 in Malta. You can take the ferry from Pozzallo to Valletta in Malta:
https://www.aferry.com/pozzallo-malta/

Have been to all three, enjoyed them all, but strongly agree that trying to "do" all of them in 2 weeks is Not A Smart Choice - add in Greece as well? Yikes...

We did a lightning-fast blitz of a few highlights on Sicily (as part of our first trip to Italy) - we were there (Sicily) less than a week and it was obvious we could have spent a month there easily. I think for most folks, you need 10 days to 2 weeks as a minimum.

We spent 19 days in Sardinia. We moved quite quickly (many here would say too quickly) and we still had to skip many places we had wanted to see - we left wishing we had at least another week there.

We spent 12 days in Malta - we covered a lot, but still skipped many things we had hoped to get to. We could have (should have) spent at least a few more days there. I'd say for most people, 10 days is probably a good minimum for Malta, for us, 2-3 weeks would be better.

Of course it's your trip so do what you want, but IMHO you really need more time (a lot more) to see these places. They are not small, and are all filled with plenty of great things to see and do. While Malta is somewhat smaller, it's also much more densely packed.

Trying to "do" all these places in such a short time will leave you with an "If it's Tuesday, this must be Belgium" experience. Make better use of your limited time: slow down, and pick ONE of these places and spend your two weeks there.