Does the Greek word for obey in Ephesians 6:1 and Colossians 3:20 mean obey without question or is there room for discussion?

Ephesians 6:1:   Τὰ τέκνα, ὑπακούετε τοῖς γονεῦσιν ὑμῶν ἐν κυρίῳ, τοῦτο γάρ ἐστιν δίκαιον

Colossians 3:20:   Τὰ τέκνα, ὑπακούετε τοῖς γονεῦσιν κατὰ πάντα, τοῦτο γὰρ εὐάρεστόν ἐστιν ἐν κυρίῳ

Naive answer: certainly in Modern Greek, υπακούω is straight out “obey”.

Etymologically it means “under-listen”; and the first gloss given in Liddell–Scott is “hearken, give ear”: that’s the sense it has in Homer. That sense definitely has wiggle room: it just means “consider what is said”.

The meaning shift from “hearken” to “answer, respond” to “heed, comply” to “submit”  to “obey” happened during Classical times: LSJ says “submit” is already in Herodotus, and “obey” in Thucydides and Xenophon.

Did the original, Homeric meaning stick around in the Koine?  Probably not. The BDAG dictionary (of New Testament Greek) gives the definitions “to follow instructions; to obey, follow, be subject; to grant one’s request; to answer a knock at the door”. That doesn’t sound like wiggle room to me.