I’ve had both, both good but the TCR is the better bike as an all rounder. Lighter, steers better and climbs better. The propel is an aero bike and wins on flat roads on calm days.
TCR has come top for years in most bike reviews. Just my opinion and as always best advice is to ride them both
Shame on you not being able to keep up on one gear....I do chain gang on mine and make it round !