Yeah the lack of focus on the strawhats has definitely been a big issue of post timeskip. In Wano people blamed the ridiculous amount of side characters as the reason why they got so little focus but now in Egghead, an arc with a much smaller cast, we can see that this was not really the reason.
In fact the Strawhats have never been as irrelevant to the plot as they are in egghead (outside of Amazon Lily-Marinford of course). Even Zoro and Sanji, while still getting more to do than the rest, could easily be removed from the arc and really not much would change... This has been a trend ever since the start of post timeskip as each arc the crew get less and less to do with the notable exception of WCI. Imo the reason why is that Oda simply decided to focus more on fighting which doesn't allow the weaker strawhats to really do anything relevant.
I personally stopped expecting anything from the non east-blue strawhats, I don't think Oda really intended for them to be Main characters from the start anyway to be fully honest. But Nami and Usopp should get way more focus than they do. It would have been inimaginable back in Enies Lobby to have those two have literally no impact on the plot for an arc this long. Especially since they didn't do very much in Wano either (especially Usopp who was legitimately an NPC).
I still very much hope Elbaf will be to Usopp what WCI was to Sanji but the closer we get to it the less I believe it. As for Nami I don't even know if there is anything coming for her. Oda could easily write more for her character but he passed a golden opportunity in Fishman Island and I don't see anything that big ever coming up again. Especially since he has not been setting up anything for Nami (unlike fucking Sanji who gets like a damn thousand plot points every arc)...
Anyway whatever I'm just ranting at this point but we will see what Oda chooses to do, at least in the very final arc, be it Laughtale of the final War of whatever, Nami should be almost guaranteed to have some big contributions. In Elbaf though ? I would not bet on it