Redirecting Old Domains to Site Page - SEO Implications?

Hi All,

I have recently created a new website for my business and I would like to park/sell a load of the domains I own on a custom page on my website, but hide it from the menu - what risks are there to my main site of doing this and ae ther any solutions to ay potential risk you suggest?

For example;

mywebsite.com is my busines site, and I want to park/sell domain1.com.

I was going to create a page on my site - mywebsite.com/forsale
redirect all domains to a landing page with a contact us form to buy domain and below that some adsense ads (is this even allowed?)

is there a way to safely segregate mywebsite.com/forsale from the sitemap and your site? So for example if I had a domain that in fact was a penalised PBN in the past, would that impact my site?

Any advice or potential alternative solutions is greatly appreciated!

Buy another domain. Why would you mess them with your business? Either way, even if you don't put the pages into the sitemap, crawlers will pick them up.