Why won't my Mac go to sleep?

There is no reason to ever install or run any 3rd party "cleaning", "optimizing", "speed-up", anti-virus, VPN or security apps on your Mac.  This documents describe what you need to know and do in order to protect your Mac: Effective defenses against malware and other threats - Apple Community and Recognize and avoid phishing messages, phony support calls, and other scams - Apple Support.  

There are no known viruses, i.e. self propagating, for Macs.  There are, however, adware and malware which require the user to install although unwittingly most of the time thru sneaky links, etc.   

Anti Virus developers try to group all types as viruses into their ad campaigns of fear.  They do a poor job of the detecting and isolating the adware and malware.  Since there are no viruses these apps use up a lot of system resources searching for what is non-existent and adversely affect system and app performance.

There is one app, Malwarebytes, which was developed by a long time contributor to these forums and a highly respected member of the computer security community, that is designed solely to seek out adware and known malware and remove it.  The free version is more than adequate for most users.  

Unless you're using a true VPN tunnel, such as between you and your employer's, school's or bank's servers, public VPNs provide false security from a privacy standpoint.  Read these two articles: Public VPN's are anything but private and Security Risks: The Dangers of Using Free VPNs (eccu.edu)

Uninstall Intego according to the developer's instructions.

Open Activity Monitor in Utilities>View>All Processes>Energy tab, sort on Preventing Sleep, any listed?

If you want to be sure all of its various components are gone, the easiest way to be sure is to download and run EtreCheck.

Instructions: How to use the Add Text Feature When Posting Large Amounts of Text, i.e. an Etrecheck Report - Apple Community

You can post its report here if you wish, or just examine it yourself for any references to "Intego". As I recall it installed a plethora of kernel extensions and various system-altering components, and its uninstaller's effectiveness was less than 100% perfect.

Unlike the aforementioned junk you can get rid of EtreCheck by merely dragging its app icon to the Trash. Or, just leave it be. It does exactly nothing when it is not actively running.

Uninstall "Intego". Rule 1 of Macs is don't install junk.

Yes. When I installed "Intego" for evaluation purposes a while ago it resulted in the worst performance degradation of any similarly categorized product. No knowledgeable Mac user would consider it even remotely acceptable. Don't use those things. They're all junk that vary only in how awful they happen to be, and how difficult they can be to get rid of. Certain such products (not Intego) require nothing less than completely erasing the affected Mac to remove them.

Read Effective defenses against malware and other threats - Apple Community.

What you're checking every year are advertisements. There is no truth in advertising clause on the Internet. Those websites, blogs, reviews, posts, publications, etc exist for the sole purpose of selling you garbage you don't need, no matter how "safe" and "effective" and "recommended" their sycophants are so fond of parroting.

You will never find a website, review site, corporate lobbyist, social media influencer or industry trade publication that tells you not to buy something. I just did.