Learn English – the difference between “in the opinion” and “to the taste”

Blurry can always be replaced by blurred (except in the word blurry-eyed), but not always vice versa. IMO, blurry, for the most part, fits all three meanings of blurred in the OALD excerpt, not just the first.

However, blurred has another use which blurry doesn't duplicate, and the dictionary doesn't bring out (probably because it's hard to do without examples). When blurred follows is, was, etc., (i.e. the picture was blurred), it can take a modifier or modifier phrase (e.g. the picture was blurred by the rain or the picture was badly blurred). Blurry cannot be used nearly as extensively in this way.

To go into nuances, even in the places where blurry and blurred are interchangeable, blurred suggests a previous state of non-blurriness and may suggest a perpetrator, whereas blurry only reports the state of the object and doesn't connote much more. The distinction is, however, only slightly observed in common usage.

Perhaps you are looking at the wrong dictionary. At Synonym.com, you will find various clusters of meaning for the verbs manage and control. They overlap and are shown as synonyms in one sense. Of course that does not mean they have identical meanings. Also note that control is also used as a noun, and that is not true of manage.

Synonyms for manage

Sense 1: pull off, negociate [sic], bring off, carry off, succeed, win, come through, bring home the bacon, deliver the goods

Sense 2: deal, care, handle, control, command

Sense 3: cope, get by, make out, make do, contend, grapple, deal, act, move

Sense 4: oversee, supervise, superintend, administer, administrate

Sense 5: wangle, finagle, achieve, accomplish, attain, reach

Sense 6: do

Sense 7: wield, handle, manipulate

Synonyms for control

Sense 1: command

Sense 2: hold in, hold, contain, check, curb, moderate, restrain, keep, keep back, hold back

Sense 3: operate, manipulate

Sense 4: manipulate, keep in line, interact

Sense 5: verify, test, prove, try, try out, examine, essay

Sense 6: see, check, insure, see to it, ensure, ascertain, assure

Sense 7: see, check, insure, see to it, ensure, ascertain, assure, verify

Sense 8: master, know