It is more than plausible imo and it's not a guess. I'd bet on it. Every feature screams Clematis. Opposite foliage, variable leaf shape, long flexible petioles, petiole attachment, joints, texture, veination, everything. I just don't know which species would occur in Texas.

I agree with floral. That is definitely a clematis and very likely C. pitcheri, a Texas native. (see photo below)

FWIW, plant ID apps are notoriously inaccurate and floral's ID skills surpass all of them. She knows her plants!!