I have a website and I want to promote it on different social media platform. However, I don't want to be treated like spammer...
Don't make your website look like something terrible to people and then you won't be treated like one
Can I use another domain to promote my website? ... website is about product reviews such as gadgets and other accessories.
If you had some wonderful website with different major sections, then I'd say yes have multiple domain names pointing to quality content.
For example, I will use other domain to redirect to my original website's landing page. That page is specially designed to attract users. Are such redirects wrong?
Take a look at: https://support.google.com/webmasters/answer/2721311?hl=en
They describe your intention of new domains as "doorway" pages because the first page (which is the new domain) offers no useful content, only a way to get to the next page (a.k.a. doorway). It is nice that you cut part of the inconvenience to the users by not making them click a lonely link for them to get to the real content but there is still inconvenience because users have to first wait for content (the redirection) to load from the new domain then they have for the real page to load. Why not just ditch the inconvenience and have users wait for only ONE page rich in content to load?
If so is there any other way I can promote my site?
Talk to people? Make rich quality content that people want to see, and use search analytics in google search console to see what queries people use and how many enter your site as a result.