I attempted to park multiple domains, but I'm not happy with the way you can't customize texts, promote the domain, or explain things properly, plus the overall design is not great.

For my other domains, I now use my html template - I can design everything how I want which, in my view, improves sales, but it's a hassle to update info, check stats, and so on.

Because of this, I plan to set up redirects from each domain that I'm selling to a single site.

I want to install a metric there, automate processes, among other things.

Are there any issues that could arise with indexing for the domains that have the redirects, or could there be any penalties from the PS?

What would be your advice on organizing all of this?

When you set up redirects, you'll want to use 301 redirects instead of 302. A 301 redirect indicates that the move is permanent, and this tells search engines to transfer any link equity from the old domain to the new one. If you use a 302 redirect, it suggests that the move is temporary, which might lead to less efficient indexing.

Secondly, there can be some impact on indexing. If you have multiple domains redirecting to one central site, you might lose some of the visibility that those individual domains had. This means the unique traffic and potential ranking benefits from each domain may diminish. However, this shouldn't be a significant issue if your main site is optimized for SEO and provides high-quality content.

As for penalties from the search engines, as long as you are not engaging in spammy practices like sneaky redirects or creating a doorway page, you should be fine. It's essential to ensure that the redirected domains lead to valuable content, or you may risk being viewed as manipulating search engine rankings.

To organize this process, I recommend the following steps:

1. Choose a clear, cohesive theme for your single site that can accommodate various niches represented by your domains.

2. Implement the 301 redirects from each domain to appropriate pages on your central site to maximize relevance.

3. Set up Google Analytics or another metric tracking tool to monitor traffic and conversions. This will help you see how well your redirected domains are performing in relation to your new site.

4. Automate as much as possible. Use plugins or scripts to manage tasks like updating info or checking stats, so you don't have to do this manually all the time.

5. Be transparent about the redirecting strategy on your site. Explain to your visitors why they are being redirected and what value they will get from the new site. This can help build trust and improve user experience.

6. Keep an eye on your backlinks. If there's a significant amount of traffic coming from links pointing to your redirected domains, consider reaching out to update those backlinks to point directly to your main site.

7. Regularly check your site's SEO performance using tools like Google Search Console, to identify any issues with indexing or crawling.

Having a blank page is preferabel to a redirect. If you must use a redirect, it shouldn't be permanent, unless the domains are somehow connected. It's more wise to create a polymorphic template that all the domains can point to.

You should also include the code there for collecting all the essential statistics. By doing this, you'll be able to keep track of your visitor data more effectively, which is crucial for improving user experience and optimizing your site.

You can easily manage all your domains on a single hosting service. First, you could register numerous aliases for your primary domain. This way, no matter which address someone visits, they will see the same site. To tailor content for each specific domain, you can insert some code that swaps out the information based on the domain name.

You should gather all relevant data from the database or another source using the hostname. I know of a hosting provider that allows for an unlimited amount of domains and has an accessible API specifically for adding more domains. You can even manage these domains directly from your dashboard, remotely if needed. Additionally, C-panel offers a similar API, which is useful if you plan on creating a full-fledged parking script complete with a control panel. However, that might not be necessary for you just yet. If you own a server or VPS, you could set up the parking script as the default handler without having to input the parked domain names into the web server configuration.