A hairdryer for an hour or two ? 😵💫
To put that tyre into the oven, the OP is going to have to take it off the rim again unless he’s got a very big ovenHe may or may not be willing
Personally I’d come back to it later and then admit defeat and down to the LBS with it
No idea what a tyre insert is so I won’t be trying those.
5 minutes with the hair dryer, and you would warm the tyre before fitting it on the rim. Tyre inserts mean if you ever get a puncture on a ride you can just carry on , a bit like a run flat on a car. I am purely trying to give really useful tips.
