For the larger crapes, I prefer those with a broad and/or weeping habit. If you're the same, you might consider Commanche, Miami, Osage, or Tuskegee. Lipan falls into that category, too. All have exceptional bark interest, high mildew resistance, and great fall color. I think that Biloxi has an upright growth habit, and Wichita is a bit smaller than the others. I'm glad to see that someone appreciates Crape myrtles as a shade provider! These trees won't be topped! ;-)

Do you have many squirrels or other wildlife (deer, opossum, ...) in your area? If so, there's a good chance some of them are behind the crape myrtle trimming. Squirrels eat or experiment with all sorts of things, especially during the intervals between their primary fruit and nut foods. They remove several flowering tips from our crape myrtles every year... as well as an occasional bedding plant, turf runners, and small branches or bark from other trees. Some birds do eat the seeds, though they don't seem to be a favorite with our year-round locals while alternatives are still available. Sorry you're living with the frustration of stuff disappearing from your property. A security camera could help figure it out, just be sure to get one with good low light capability in case the "critters" causing your losses are nocturnal. At least your young resilient CMs should be fine. Here is a link that might be useful: Goldfinch and crape myrtle seed

I follow a blog on Southern Living's website by Steve Bender, and he just posted about pruning crepes saying that now is a good time to do it. I linked to the blog post below, partially because there's a link at the bottom of the page to another blog post describing the correct way to prune a crepe myrtle, but mostly because he's running a contest right now where people submit pictures of badly pruned crepe myrtles. The winners get a prize! Here is a link that might be useful: The Grumpy Gardener

What about something like Orange Rocket Barberry Bushes? They get max 4' tall x 1½' wide, and are somewhat cylindrical. They are very colorful with coral/orange leaves with lime edges. Many Texans are posting gorgeous photos of theirs on my other garden forum (but they are deciduous, so they lose their leaves after spectacular burgundy color in the Fall, leafing out with lime green leaves in Spring). They seem to do well in Texas. I just ordered some thru Walmart and I'm here to say that they that were some of the best-packed, healthiest plant specimens I have ever ordered from ANYPLACE on-line. Been in the ground 2 weeks and loving the sandy soil at our cabin property in Gause. https://www.walmart.com/ip/Orange-Rocket-Barberry-Live-Deciduous-Shrub-with-Colorful-Foliage/49094501?wmlspartner=wmtlabs&adid=22222222222036989139&wmlspartner=wmtlabs&wl0=e&wl1=o&wl2=c&wl3=10355304266&wl4=pla-1103074146087&wl12=49094501_0amp;wl14=%27Orange%20Rocket%27%20Barberry%20bush%20for%20sale&veh=sem&msclkid=797e9b46446919e2e048c6e69e51fca1. Perhaps these planted alternately with something that isn't deciduous so there would be color and foliage in your median in winter as well. Winter Daphne (nice blooms, evergreen throughout winter) and a lovely scent as well. They're pretty compact, too. https://www.waysidegardens.com/variegated-daphne/p/v1829/?msclkid=bffb8e9c489613230442d33c94b67df0&utm_source=bing&utm_medium=cpc&utm_campaign=Google%20Shopping1&utm_term=4582420873088447&utm_content=Vines%20%26%20Climbers