And then there’s the whole issue of sticking q-tips with crazy glue in the jack, for all I know I’ve glued it in permanently
Heat will break a crazy glue bond, but it will be hard to get a localized application of heat sufficient to break the bond without melting plastics nearby. I would look at replacing the jack outright. What model is the amp?
Acetone also works to dissolve crazy glue but also dissolves some plastics (ABS) so you have to be careful where you use.