You should avoid installing any older versions of Flash Player on security grounds. The change is unlikely to affect your daily browsing habits since the vast majority of websites have stopped using Flash in favor of modern browser technologies.
This also means that versions of Flash bundled with browsers like Google Chrome will be retired. There will be no more updates to Flash, nor will you be able to download old versions directly from Adobe. The company recommends that you uninstall Flash entirely as a matter of security. Flash is no longer available to download since December 31, 2020, and Adobe starts blocking Flash content from running altogether on January 12, 2021.