Help in understanding if my Mac has a virus/malware?

Of the three you posted, the results are 100% clean. So why are you even concerned about them?

As already noted, you're completely wasting your time and system resources with useless AV software. Delete them and never look back. The suggested MalwareBytes for Mac is about the only useful such software on a Mac as its main purpose is to look for malware you may have already installed and then remove, not prevent it.

Yes, a virus is malware. So is a Trojan or worm. The word malware is a generic, catch-all phrase that stands for malicious software.

There are no viruses on the Mac. Zero, nada, zip. Worms are almost non-existent. The last reported, known worm was from over a decade ago.

There are lots of Trojans, which is any malware the user needs to install in some manner. It can't get on your Mac by itself. These include key loggers, back doors, adware, ransomware, etc.

You're worrying far too much about next to nothing. Yes, there were PDF and JPG exploits, but those were years ago and have been patched against. And places like VirusTotal go very much out of their way to find something, anything, that might be suspicious. It's how they keep people coming back. Fear.

Literally, any third party file you open, whether it's an app or data, has the possibility of including malware. All a perp has to do is add code to the file that isn't supposed to be there. The OS (doesn't matter if it's Windows, Linux, macOS, etc.) has to read the file from start to finish. In the process of doing so, it also reads and executes the attached malware.

But!, you can drive yourself crazy trying to find that 1 in a million files that may be infected. And you almost have to intentionally try to get one.

How do you avoid a Trojan? It's actually very, very simple:

Get your third party apps from reliable sources only. That means only from the original vendor. Never - and I do mean NEVER - from a P2P, file sharing or pirate site.

Beyond that, read this excellent treatise by fellow user, John Galt:

https://discussions.apple.com/docs/DOC-8841

And just to give you an idea of how little I worry about such things, I haven't used any type of AV software since the release of Windows 95. And then I only had it for the year of updates it got, realized I was wasting computer resources looking for nothing, and removed it.

It's all bogus and you need to get rid of all the AV scanners and any "helper" type apps you have installed and disregard the websites. That just want you to ultimately buy a product. None of them are of any use and locally installed apps often disrupt system operations.

There are no Mac viruses in the wild and if you have malware, what you need to do is scan for it specifically

Download and install MalwareBytes (the free version is all that's needed) then run the scanner to remove any malware that may be present.

https://www.malwarebytes.com/

Nothing to worry about there. The Mac OS is sealed in a read only partition that prevents any viruses from changing its system files. Virus Scanners for a Mac are only there to scare you into giving them money to solve a problem you do not have. You should not use any Virus Scanners or apps that claim to speed up your Mac.

As noted above MalwareBytes is the only app that has been shown to be helpful with Malware. Even with this app, you would only want to do the free scan and there is no need for constant monitoring. Malware is different from Viruses and will not infect files on your computer. Malware usually gets installed through a web pop up that claims to do one thing, but does something else. The most common pop ups are from virus scanners or a fake "Update Flash Player" pop up. The symptoms of Malware are notifications or popups that claim you have a problem and want you to spend money to fix it. Another type will redirect your web searches to another site to display more ads. These are not viruses and will not be detected by virus scanners. Malware is easily removed and is always inadvertently installed by you and does not spread. You will know when you have Malware, because its only motivation is money and it will make its presence known by a constant barrage of notifications or ads to generate money for them.

If you want greater flexibility in a demo/free app, you buy the full version. In this case all you need is the full machine scan of the free version. Don't worry about individual file scans, they're covered in the full scan.

The PDF exploit was at least 5 years ago. Likely more. And they weren't something you just randomly ran across. They almost exclusively came attached to spam emails. The favorites were a fake delivery or invoice PDF from DHL; or a FedEx (or UPS) notice that you needed to pick up an undeliverable package.