Is WP Multisite the right way to go?

Hi guys, I’m planning to sell blog themes on my website where customers can view a demo version of each theme (either in subdomains or subdirectories). I’m hoping to set up 6-12 themes eventually. Is this something where it makes sense to use WP Multisite plugin? Or should I just have a separate WP account for each of my demo sites? Which method will be easier to manage if I ever need to make changes across all my demo sites? I’m pretty new at web development.

Any feedback is appreciated, thanks.