There are definitely AI upscalers as some other users mentioned. I would scan the photo first though so you have the best possible digital copy of the photo before trying to upscale it.
Here's what my Pixel did with perspective correction and some spot removal to get it to full-frame, along with the AI unblur function turned all the way up.
There are ways to upscale or increase the resolution of the image, typically done using AI/ML. If you want to try it for free I've found this site to let you mess around with some AI features for free - https://www.fotor.com/photo-editor-app/editor/ai
AI, but it will invent / draw the blur parts and may be somehow feel fake. I mean there is no magic in photography, what is missing only can be recreated.
Sorry, focus is the one thing that can't be fixed in post by traditional methods. AI can attempt to make it better but often times the result looks like it was obviously AI generated.. since well, it was.