A 301 Redirect Is a Good Way to Link Two Sites
If you run a popular site in a competitive niche and have the opportunity to buy a high traffic competitor's website, should you do it? If you do, you'll have to decide whether you want to run them as separate sites or redirect traffic from the new domain to your existing site.
Running two sites will give you more real estate in the SERPs and it gives he person searching the illusion of options. If you can logically split your site into two distinct websites with different products, this may work. You can use one to have a highly focused product offering.
It is a lot of work to keep two sites ranking well. A single website is easier to maintain than two websites. It's also harder to cross sell if a complimentary product is on another website. You would also have to build a brand from scratch for the domain you just bought.
Linking your two sites is usually fine as long as you are transparent about what you're doing. No one really knows how Google determines link scheme penalties, but there are many sites which split their content, otherwise, their main site would be huge. They operate under different brand names, however; they make it clear they are the same company.
You can redirect visitors from the domain you bought to your primary website with 301 redirects to take advantage of existing traffic. You should be able to pass on some of the site's link juice to your main website. There is another option; you could redirect your existing site to the new domain you purchased. This may be an option if they new domain has many backlinks and great organic traffic.
No matter what you ultimately decide on, you should do a complete audit of both sites before making any decision. For more information click here https://www.reddit.com/r/SEO/comments/cify11/succesfullypurchasedlargecompetitorsite_in/.