It's not often a verse is so confusing. Actually, there are lots of times this is the case. But there are two confusing things here; one is high level confusing but with low level impact, while the other is normal level confusing but with greater impact.
So the very weird thing: differing versification between Greek and English.
NIV (cf. ESV, CSB etc etc)
2:6 We were not looking for praise from people, not from you or anyone else,
even though as apostles of Christ we could have asserted our authority.
2:7 Instead, we were like young children among you.
Just as a nursing mother cares for her children,
NA28 (cf. USB5 etc)
2.6 οὔτε ζητοῦντες ἐξ ἀνθρώπων δόξαν οὔτε ἀφ᾿ ὑμῶν οὔτε ἀπ᾿ ἄλλων,
2.7 δυνάμενοι ἐν βάρει εἶναι ὡς Χριστοῦ ἀπόστολοι,
ἀλλ᾿ ἐγενήθημεν ⸀νήπιοι ἐν μέσῳ ὑμῶν.
ὡς ἐὰν τροφὸς θάλπῃ τὰ ἑαυτῆς τέκνα,
I guess it's not super-weird, but I can't remember seeing the versification being different within a verse. Normally it's a different chapter division (cf. eg. Eccl. 4.17MT = 5.1Eng.), which affects the verse counting, but this is the first time I've seen it change within a verse.
What's doubly weird is I can't find anyone who cares to speak on it. The critical commentaries I've looked at either don't mention it or just note it with no explanation or discussion. The reason for this is that it doesn't affect anything, but it's still weird, and it musses up the cross-highlighting in Accordance.
The less weird thing: textual variant: the dropped or added Ν
As you can see above, there is a text critical mark before νήπιοι, which tells us that in some manuscripts the reading isn't νήπιος (infant), but ἤπιος (gentle). It's a pretty straight-forward case: either someone added the N to ἤπιος because they liked the imagery - there's also mother in 2.7 and father in 2.11, plus Paul likes νήπιος, using it 15 times in his letters. The alternative is someone removed the N, because they didn't want to mix the metaphor, making this one of only two times Paul says ἤπιος (the other being 2 Tim 2.24).
I guess if you don't agree with Pauline authorship of the Pastoral Letters you would say it has to be νήπιος, as ἤπιος isn't a word Paul uses. Although you probably don't think he wrote the Thessalonian correspondence either, so whatever.
What's frustrating is in context it could really be either. But it does change how you structure the sentence. If you letter, rather than number, the clauses as follows, there are really only two ways to structure it, and it all hangs on your text critical decision.
NIV (cf. ESV, CSB etc etc)
A We were not looking for praise from people, not from you or anyone else,
B even though as apostles of Christ we could have asserted our authority.
C Instead, we were like young children among you.
D Just as a nursing mother cares for her children,
NA28 (cf. USB5 etc)
A οὔτε ζητοῦντες ἐξ ἀνθρώπων δόξαν οὔτε ἀφ᾿ ὑμῶν οὔτε ἀπ᾿ ἄλλων,
B δυνάμενοι ἐν βάρει εἶναι ὡς Χριστοῦ ἀπόστολοι,
C ἀλλ᾿ ἐγενήθημεν ⸀νήπιοι ἐν μέσῳ ὑμῶν.
D ὡς ἐὰν τροφὸς θάλπῃ τὰ ἑαυτῆς τέκνα,
Option 1: If you go with νήπιοι/infant, then you have to have one sentence = ABC. New thought: D...
Option 2: However if you decide it should be ἤπιοι/gentle, then your first sentence = AB. Next sentence: CD...
In the first option, infant is describing Paul's refusal to assert his authority. He asserted the same authority as an infant can, that is, none.
But in the second option, gentle is describing a nursing mother. The lack of authority is not further explained, but the character of a nursing mother to her child is: Paul & Silas became gentle among them, just like a nursing mother to her children.
Funnily enough a lot of ancient texts bear witness to both, with νήπιοι the original reading, later corrected to ἤπιοι. So on the weight of that, infant makes sense. But both work. The NA28/UBS5 went with νήπιοι, while the new THGNT has decided on ἤπιοι. Similarly NIV chose infant, while the ESV chose gentle.
Ultimately it's up to you, but hopefully this is a clear enough presentation of the options for you to make sense of.
