TX-30 is centered on heavily black and Hispanic South Dallas, as well as the heavily black suburbs south of Dallas, while TX-33 is centered on heavily Hispanic West Dallas and western suburbs as well as big chunks of Fort Worth.
All of these areas are growing and growing faster than the state average, even if not growing faster than the suburban boom areas. TX-30 and TX-33 will both have to be significantly physically smaller in their next iterations (TX-33 might well be kicked mostly out of Dallas to just be a Fort Worth and Mid Cities district due to Ft Worth's growth). This is a huge problem to the GOP because these seats are as Dem packed as can be. TX-30 can either take itself further south, giving the northern parts of it to TX-32 and TX-05, or pull itself north and give all of the suburbs south of Dallas to TX-06, dragging TX-06 into Dallas County. TX-33 shrinking in west Dallas and the west Dallas suburbs risks dragging TX-06 again or TX-24 into those areas.
That is actually not quite true. From 2017 population estimates by CD, the TX statewide growth rate from 2010 to 2017 was 12.6%. The national growth rate was 5.5%. TX-30 (10.9% growth rate) and TX-33 (7.9% growth rate) are both slower growing than the state average, although they are a bit faster growing than the national average. Since they are still faster growing than the national average, it is nonetheless probably (depending on rounding error in reapportionment) true that they will indeed have to give up a bit of territory in redistricting, but not all that much.
The Houston area is a bigger problem for the GOP in this respect than the Metroplex. In Houston, TX-18 (14.6% growth) and TX-09 (13.0% growth) are both growing faster than the statewide average, although TX-29 is a bit slower though still faster than the national average (9.1% growth).
More broadly, the real problem for the GOP is that out of the 3.2 million people TX gained since 2000, only 458K (14.5%) of them were white. Just the black population growth of 443K (14.0% of the total growth) is enough to offset the political effect of the white growth, even if you assume that Republicans are overwhelmingly winning the new White growth by 80%-20% or so - which is not a sensible assumption.
What white population growth there is tends to be a bit more concentrated in the most white-liberal of the big TX metro areas - Austin, with white population loss across the rural districts (and rural parts of non-rural districts) and also some white gains in the fastest growing and most Dem-trending suburban districts (where the white share of the population is nonetheless quickly decreasing because the non-white growth is much higher - like TX-03, for example, which although it gained 56k whites, it also gained 116k non-whites, and has been one of the most strongly Dem trending areas of TX in 2016 and 2018).
It is interesting to make a list of all the Congressional districts where the White share of the district's population growth is higher than the statewide average:
TX-25 (56% of the population growth there is White) --- White liberal Austin population growth.
TX-26 (46% of the population growth there is White) --- Denton/DFW suburbs that have trended strongly Dem
TX-08 (41% of the population growth there is White) --- This is basically the only real counterexample where the GOP is okayish in terms of the population growth and people voting R.
TX-31 (37% of the population growth there is White) --- North Austin Williamson County suburbs, where Beto shockingly won Williamson County...
TX-04 (35%) --- This is the 2nd best counterexample other than TX-08, but all the white population growth is basically in Rockwall County in the Dallas suburbs, ie the only part of TX-04 that has trended D.
TX-21 (33%) --- More Austin white liberals.
TX-03 (33%) --- Collin County.
TX-35 (32%) --- Dem Austin Hispanic VRA vote sink getting more white liberals.
TX-12 (29%) --- Fort Worth/suburbs.
TX-10 (26%) --- Austin white liberals and some NW Houston.
TX-22 (23%) --- Fort Bend.
TX-17 (20%) --- All the white population growth in this district is in the North Austin part of the district and in College Station, both of which trended strongly Dem in 2016 and 2018.
That is it. The complete list of all Congressional Districts where White growth is a greater share of the growth than the statewide TX average. Other than TX-08 and TX-04, every last one of them is trouble for the GOP, and about half of those districts are districts where the White growth is in the Austin area.
Every other district has either a lower White share of the growth, or has outright White population loss (Fully 17 Congressional districts in TX have outright White population loss, despite having overall population gain thanks to non-white growth).
TX-24 is probably the best example of this GOP problem with white population growth either not existing, consisting of Austin white liberals, or just getting swamped. Although TX-24 gained 102k people since 2000, it actually had outright white population
loss of -8k. And 30k of the 120k non-whites it gained were black. That is obviously not a winning long term formula for a whites-only Republican party.
So I would say that the major part of the problem is simply that these suburban areas like TX-24 are just shifting under the feet of their R incumbents, less so than whether they have to take more territory from districts like TX-30/TX-33. The problem is not new territory, it is the territory that they already have, and that used to be much safer R than it now is. The problem for the GOP is places like Sugar Land are now starting to vote Dem, and you are starting to see Dem-voting precincts spring up in places like... Frisco !?!?!