It’s going to depend on what the shoes are made of... There is a product by Kiwi called Universal Shoe Stretch that is supposed to work on all materials except those that are man made (i.e. vinyl or faux leather). For vinyl or faux leather, thick socks can be worn with the shoes while using the heat from a hair dryer on the shoes (please do so at your own risk!). I would not recommend a heat gun because the extremely high heat will cause burns or melting. I hope this helps!
They sell cedar shoes stretchers. they're wood and are screwed together. you put 'em in the shoe and slowly spread them apart until you get your desired shape and then usually leave overnight. Get them at any shoe store or CVS, rite aid, that sort of thing or check out this link: https://www.amazon.com/s?k=shoe+stretchers&i=garden&ref=nb_sb_noss
It’s not worth it. Take the hit and get a proper fit at a shoe store.
A shoe salesman once told me to pour rubbing alcohol into the shoe then wear the shoe until it is dry. He said that is what they use at the store to stretch shoes. They pour alcohol into the shoe and put the shoe on the stretcher until it is dry. I've not tried this but I know alcohol dries pretty quickly.