Origin of "curse"

I am reading a Harry Potter book and came across the word "curse". I realized I had no idea what the origin of "curse" was. I searched it up and below are my search results.

of uncertain origin

This is what Etymonline says:

curse (n.)

late Old English curs "a prayer that evil or harm befall one," of uncertain origin, perhaps from Old French curuz "anger," or Latin cursus "course." Connection with cross is unlikely. No similar word exists in Germanic, Romance, or Celtic.

'Curses' as a histrionic exclamation is from 1885.

The curse "menstruation" is from 1930. Curse of Scotland, the 9 of diamonds in cards, is attested from 1791, but the origin is obscure.

curse (v.)

Old English cursian, from the source of curse (n.). Meaning "to swear profanely" is from early 13c. Related: Cursed; cursing.

Does anybody know the origin of curse and/or have some links they can point me too? I am looking for an origin further back than OE curs as I already have found that.

In a piece for the Oxford University Press, Etymologist Antony Liberman makes a long, detailed and very interesting account of all possible origins of curse and concludes that:

In my opinion, the verdict origin unknown should be used only when there is really nothing to be said about a word. In other cases, a summary, however cautious, would be helpful, for example:

1) Curse. [Attested forms] The derivation from cross, though often suggested in the past, cannot be substantiated.

2) Unlikely are also the derivations by L. Spitzer from Latin (in)cursus ‘the fact of having incurred a penalty’ and 3) by E. Weekley from Anglo-French curuz ‘wrath.

4) A Germanic source (Otto Ritter) is even less likely.

5) By contrast, the derivation from Latin cursus ‘a formula for excommunication, etc.’ (The Century Dictionary and Middle English Dictionary), sounds convincing. Rather probably, the Latin formula merged with a borrowing of Old Irish cúrsagad ‘reprimand’ and yielded the modern form, which then is a blend.

This is not a great entry, but, admittedly, better than nothing. And if the idea of cúrsagad, from curas agere, and cursus having produced the modern form is correct, we know everything about Engl. curse we would like to know!

(blog.oup.com)