E-inside-o / o-enclosing-e variant of German ö

[Sai]

Hello all.

Does Unicode have an existing way to encode the e-inside-o /
o-enclosing-e* variant o-e ligature for German ö?

See e.g.:
* the ö in Vögeln on the cover of 1st edition of Konrad Lorenz's _Er
redete mit dem Vieh, den Vögeln und den Fischen_
https://en.wikipedia.org/wiki/File:ErRedeteMitDemViehDenV%C3%B6gelnUndDenFischen.jpg
- n.b. other editions have normal ö; I do not know if it's used inside
the book in normal or heading texts, or just on the cover
* the ö in Köln (English: Cologne) in the inscription of its
cathedral's crypt
https://commons.wikimedia.org/wiki/File:O_containing_E_ligature.jpg

I do not know whether it is used in any language other than German,
nor how widely used it is for German.

There's a CC by-sa SVG of the capital version here:
https://commons.wikimedia.org/wiki/File:Latin_capital_letter_O_containing_E.svg
— but I don't know of a lower-case version.

There exist Unicode:
* Ⓔ U+24BA and ⓔ U+24D4 — circled latin capital/small letter e, in the
Enclosed Alphanumerics block
* Œ U+0152 and œ  U+0153 — Latin capital/small ligature oe, in the
Latin Extended-A block
* ɶ U+0276 — Latin letter small capital oe, in the IPA Extensions block

However, Ⓔ/ⓔ use a circle (not letter o), and don't decompose to ö or
œ; and I have not found something that does decompose to œ which would
use the enclosed ligature.

I don't know combining characters well enough to tell if there is a
combining version of either o or e which would allow this.

So… is this already a thing? Has it been proposed before? Ought it be
added to Unicode?

Sincerely,
Sai
President, Fiat Fiendum, Inc., a 501(c)(3)

* phrasing it both ways just so this discussion is easier to find by search