I am now using fully synthetic instead of semi synthetic engine oil on my 2020 ford escape with the 2 litre engine. Can I now lengthen my oil change interval?
No.
Depending on how long the interval is, that would be a mistake.
Scotty has a video and also mentions his recommendation for synthetic oil change intervals.
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The Truth about 20,000 Mile Oil Changes - Myth Busted
Stick with 5000 miles oil+filter changes if you want that engine to last.
a little bit, sure
5,000 - 6,000 miles