What exactly is vossagga in 5 indriya samādhi

“And what is the faculty of samādhi?

Idha, bhikkhave, ariyasāvako vossaggārammaṇaṃ karitvā labhati samādhiṃ, labhati cittassa ekaggataṃ—

ven. thanissaro has:

There is the case where a monk, a disciple of the noble ones, making it his object to let go, attains concentration, attains singleness of mind.

ven. sujato has:
It’s when a noble disciple, relying on letting go, gains immersion, gains unification of mind.

ven. bodhi has:
Here, bhikkhus, the noble disciple gains concentration, gains one-pointedness of mind, having made release the object. This is called the faculty of concentration.

Ven. Bodhi’s, the way I interpret it, sounds like ‘release’ is a code word for nirvana, and one has nirvana as the ulterior motive for attaining samadhi.

Ven. Thanissaro’s is similar, but a little more ambiguous.

Ven. Sujato’s sounds like vosagga is only a means to attain samadhi, and not a separate goal of nirvana.

Are all of of these interpretations legitimate?

I follow Bodhi’s translation, because of the very frequent 7sb formula, where vosagga clearly is referring to nirvana:

STED (7sb) satta -(sam)-bojjh-aṅgaṃ

STED (7sb) seven awakening factors

1. Sati

sati-
(the) Mindfulness-
-sam-bojjh-aṅgaṃ
-***-awakening-factor;
bhāveti
Develop (that)!
viveka-nissitaṃ
seclusion (is) necessary
Vi-rāga-nissitaṃ
Dis-passion (is) necessary
nirodha-nissitaṃ
cessation (is) necessary
Vossagga-pariṇāmiṃ,
relinquishment (is what it) matures (into).

2. Dhamma-vicaya-

Dhamma-vicaya-
(the) Dhamma-investigation-
-sam-bojjh-aṅgaṃ
-***-awakening-factor;
bhāveti
Develop (that)!
viveka-nissitaṃ
seclusion (is) necessary
Vi-rāga-nissitaṃ
Dis-passion (is) necessary
nirodha-nissitaṃ
cessation (is) necessary
Vossagga-pariṇāmiṃ,
relinquishment (is what it) matures (into).

3.vīriya ... all 7 bojjhaga have that formula culminating in vosagga-