Not OP, but I use Figma to do this. There are lots of templates in the community, or you can make your own pretty easily.

If you don't want to do it as manually there are paid tools that will help. Google "app store screenshot maker" for options.

Not OP, but have a look at [0]. It’s not great, but good enough. I regularly use it for App Store screenshots with captions and text.

[0] https://theapplaunchpad.com/