I’ve been using a giant propel for 3 years on a couple different smart trainers with absolutely no issues. The only workouts I don’t do inside are full on sprint efforts, and that’s mainly because the bike doesn’t move naturally when hooked to a trainer like it does outside. The only people I know that have broken a bike while riding inside had incidents where they somehow tipped the bike and trainer over (I’ve never come close to doing this). Just be sure to use some towels to protect the bike from your sweat.