How was ‘only’ (‘onely’) pronounced in early modern English?

I have noticed in some older English literature, that ‘only’ is written ‘onely’. Was this merely an example of historical spelling, or does it reveal an earlier pronunciation not as modern /ˈəʊnlɪ/, but rather as /’wʌnlɪ/? An example:

[…] because it is upon a misinterpretable subject, I have always gone so near suppressing it, as that it is onely not burnt […]
―John Donne, in a letter of 1619 to Sir Robert Keer, as quoted in Al Alvarez: The Savage God, Weidenfeld and Nicolson, London, 1971, p. 133.

Later, in the same quote, the spelling is ‘only’, though I do not know whether this is a clerical error by Alvarez or whether Donne actually did use both spellings in the same letter. Given my (very minor) knowledge of 15th- to 17th-century English documents, and the same with Scandinavian and German documents, finding two different spellings of a word in the same document is not only plausible, but expected. Further, given what effort Alvarez has gone to to represent old texts correctly in his work, I assume it is in fact correct.

Earlier and later examples are presented by the OED:

But the affeccion of the publique well may auoyde your singuler disordinate reule yf the voluntees ben conyoined all in oon onely desire to the comon saluacion.
c1475 tr. A. Chartier Quadrilogue (Univ. Coll. Oxf.) (1974) 245 (MED)

What cannot onely Sons with Parents do!
OED: 1672 J. Dryden Conquest Granada ii. iii. ii. 109

The power was retained; with this onely difference, that [etc.].
OED: 1741 C. Middleton Hist. Life Cicero I. Pref. 35

Onely, Onerly, lonely, retired. ‘This is an onely platt to live in’.
OED: 1828 W. Carr Dial. Craven (ed. 2)

Mon, aw’m one-ly when theaw artn’t theer.
OED: 1856 E. Waugh in Manch. Weekly Examiner & Times 21 June (Suppl.) 3/3

However, the modern spelling ‘only’ is also listed as early as 1483:

I that am an only sone to my fader and moder I shold depose theyr olde age with heuynes and sorow to helle.
1483 W. Caxton tr. J. de Voragine Golden Legende 77/3

In addition to this, you of course have other older spellings, like ‘anli’ and ‘oonly’. But the later usage of the spelling ‘only’ – ɔ: after the great vowel shift – I would presume would either represent (as per my question) either: a historical pronunciation or a representation of actual pronunciation. Hence my question: How was only/onely pronounced in Early Modern English? And further: In Early Modern English, are we dealing with an historical spelling, or an actual representation of two competing pronunciations?

Note: I may be mistaken in what I understand to be Modern English, so if there is a need for me to update my question (considering the original quote), please do advise me on this.