What size torx were you using?

The most difficult bolt is the L/R under the cowl with limited access and visibility. If this is one of the stripped torx getting it out will be a challenge. This bolt only allows for about 6” extension or rise to allow for a ratchet because of the cowling.
Being they torque at 8 Lbs, unless corroded etc, they shouldn’t strip easily if the correct bit is being used.

That said, you may have luck driving the next size up bit into the head (difficult on the L/R because of access limits), or better yet with a rounded bolt extractor biting/cutting in on the outer diameter of the head. Possibly a mirror and an angle grinder to remove the head. Would be tricky though in that position, or any of the deep well positions. Visabilty is poor, access is bad.. Drilling the head off, possible, depending where or which one/s, but easy to damage the manifold.

A trick to remove stubborn bolts threaded into aluminum is to insert the driver, or socket with an extension where applicable and strike the head moderately prior to a removal attempt. Not always possible to do in access limiting positions though.

Can you give an account of exactly which ones are stripped?