HKF uses ómu in his Neo-Q but given the element on(t) (om-) n. “everything” from ᴱ√OMO whence it derives having been later replaced by √IL, I'm not satisfied. Glosses “despite that” and “regardless (of)” both relate to looking; perhaps a Q construct is possible. “Albeit” < “although it be that” < al (“completely, entirely”) + be (3rd person singular present subjunctive of been (“to be”)) + it [from Wiktionary] reminds me of nai, so perhaps ?*aquanai.
eldamo.org - Eldamo : Early Quenya : ómu

+Robert Reynolds that ómu is familiar so it's possible that I have asked this same question in this community before:)

"regardless": there could be something in that for us

"contrary to" is a phrase that would be worth exploring
there is the conjunction úsie that could somehow help

There's an option to substitute "although" in the first clause with anante "and yet" in the second clause. Though I prefer ómu.