and then re-redrawing, would be NY. I think NY lost 5 or 6 (D) seats when they did their 2020 redistricting, ending up having instances of 2 (D)s suddenly running against each other for a new "combined" seat (Nadler vs Maloney was one example). They eventually tweaked it in 2024 and recovered a couple (D)s, but it seems the damage was done.
Alternately, FL had done like TX and managed to manufacture ~5 new (R) seats.
I think the overarching issue is the idea of "gerrymandering" and the apparent SCOTUS dipping and dodging around it (since "elections" are generally handled by the states).
I found an interesting discussion about the recent realignments here and the problems that we as (D)s face - How Gerrymandering Tilts the 2024 Race for the House
and what was noted was this -
(snip)
State courts also played a role in creating Republican advantages, because courts in states where Republicans drew maps (many of them with judges elected in partisan elections) have been much less inclined to police partisan gerrymandering than their counterparts in Democratic states. Thus, while large Democratic-favoring skews have been mostly corrected through legal review, Republican-favoring skews have almost uniformly remained uncorrected. Indeed, courts in many GOP states have followed federal courts lead in declaring gerrymandering claims to be political questions that courts have no authority to address.
(snip)
The above observation is concerning. However an interesting "game changer", which has seemingly upended some of the gerrymandering (including for Congressional seats) is the "Ranked Choice" option for primaries and/or the general election. Similarly I think CA has a "jungle primary". This introduces all kinds of candidates, including independents, into the equation.
I know here in PA, we have a closed primary and just this morning, I heard a news story where some indies here in Philly have petitioned the state Supreme Court to force the legislature to change to an "open primary". They noted that PA now has something like 1 million "registered" unaffiliated/Independent voters (I think also distinguishing from some of the known-named "3rd parties" here like the Libertarian Party, Green Party, Constitution Party, Working Families Party", etc).
So I expect the whole "system" is in transition and we are in the middle of the "sausage-making" of that.