If you're using a work computer, I strongly advise not putting that on there, especially if it requires installation. At my work, we regularly scan for apps like these, as well as the physical jigglers that connect via USB. We do this for security reasons primarily. There are several built-in ways in Windows to simulate activity, I really don't see the point in downloading random apps from potentially sketchy sources.
One example off the top of my head: If you have multiple monitors, go into presentation mode with PowerPoint on one of them. This way, you can still have one monitor available to see your email and whatever chat app your org uses. If you have just one monitor, pretty sure you can still push it to the back or minimize it and it'll still work. Also, watching videos within SharePoint is another way of preventing Windows from detecting inactivity. If you use Teams, you can start a meeting with yourself (though, some orgs monitor activity on Teams, so use this at your own risk). If PowerShell isn't disabled, there's also options there.
I don't know how our Cyber and workstation teams are doing it, I work on the server team. I just know they pushed out something a few months ago about it and a few people were caught. They really don't care that people are using jigglers, they just don't want people plugging in unauthorized devices to the USB ports. And like you say, it may not actually be catching everything.
US supreme court sides with Starbucks in union case over fired employees ( www.theguardian.com )
Wells Fargo has fired a bunch of employees after finding out they were pretending to work with "simulation of keyboard activity" ( finance.yahoo.com )
Frontier Airlines CEO says the pandemic made workers 'lazy' and less productive: 'People are still allowing people to work from home, all this silliness, right?' ( www.businessinsider.com )
Frontier Airlines CEO Barry Biffle blamed higher overhead costs on workers being less productive, calling it a "society-wide" problem.
207 Hours Overtime: Japanese Man in Kobe Worked to Death ( unseen-japan.com )
A medical resident worked 207 hours of overtime in a month. His case highlights Japan's continuing problem with karoshi - death by overwork.