Installing the Stable Channel of the next version of Microsoft Edge at the system-level will cause the current version (Microsoft Edge Legacy) to be hidden. If you want to let your users see both versions of Microsoft Edge side by side in Windows, you can enable this experience by setting the Allow Microsoft Edge Side by Side browser experience group policy to Enabled.
I suggest you try to check this document that shows how to use the Edge legacy and MS Edge Chromium browser side by side.
Side-by-side experience with Microsoft Edge Stable Channel and Microsoft Edge Legacy