Separate landing pages for each of your target demographics is a good idea. While your offer remains the same for everyone but change your design slightly and your text to appeal to different demographics. Landing pages have one purpose; to convert. They don't have navigation so visitors get distracted and link to limited pages. You can use landing pages for social media or pay-per-click ads, special promotions or free trial offers.
When you create landing pages for different demographics, you need to change the wording on the page. You can't appeal to everyone with the same landing page. If you want to use the natural language your demographic speaks, have someone their age suggest the copy. If you use images of people, use an image of a person who fits the demographic. If you use social proof on your landing page, make sure it's from people in the target demographic.
Publishers often ask if multiple landing pages will help or hurt their SEO. They usually do neither, especially if you tell Google not to index them. Usually, people who build multiple landing pages use them for PPC or Facebook ads. They don't expect the pages to come up in an organic search. Telling Google not to index them also helps you avoid a duplicate content problem is only a few words change on each page.
You can also optimize your landing pages for Google if the content is significantly different on each one. Don't waste your time if the landing page has a limited time offer as SEO take time to show results. You'll need a link to your main site if people land on the page from an organic search. This builds trust even if no one ever clicks on the link. Use long-tail keywords and semantically related keywords to improve your chances of ranking well in the SERPs. For more information click here https://www.reddit.com/r/SEO/comments/eo7lod/imdoinggoogleadsformybusinessandhave/.