Flex Monthly /should/ come up with reasonable watering times and frequency, based on historic weather conditions in Houston. Perhaps try making a NEW Flex Monthly schedule, and set it up ahead of time for how often you want it to water (say every other day) and see what time it calculates is required. Making manual changes after a schedule is set up puts the responsibility on you, rather than the Rachio unit, to water properly. Anyhow, see if that comes out any different for you. But you’re right, every week in summer is silly in Houston (or most places, for that matter).
You might still check out, and post, your current Advanced settings, as that may well give us a clue. The numbers I’m seeing for times just don’t make much sense.