If you can't use locally run AI programs like EasyDiffusion and prefer Perchance, you could try Upscayl. It's a free program (on GitHub) that uses AI to upscale your images, using different filters you can chose from.
I don't know if I can post a link to the site itself here, but you can easily find it with "Upscayl github"
Woah, this looks so sleek! Thx for the link!