What can be used to replace Adobe Flash Player?

That depends greatly on what you were using Flash Player for.

For most video, HTML5.

For games, there are lots of other choices for implementing those.

For existing games, there’s apparently an open-source project or two seeking to allow those games to work, such as Ruffle.

For the security vulnerabilities or for the power consumption issues, there are lots of choices.

Check with Adobe if you wish to use Adobe alternatives, too.

Adobe announced the end of Flash in 2017.

Adobe then ended Flash Support and Flash access earlier this year, and has blocked playback with the Adobe tools.

There’s either an app upgrade available from the app provider, or you’ll want to migrate to another vendor.

In this case: https://www.workforceinsight.com/the-move-to-kronos-flash-free-is-underway-is-your-organization-ready/