Google gives Android users a way to install unverified apps if they worked hard for it(including waiting 24 hours)
(android-developers.googleblog.com)
- enable developer options
- confirm that you are not tricked
- restart phone and re-authenticate
- wait one day
- confirm with biometrics that you know what you are doing
- decide if you only want unrestricted installs for 1 week or forever
- confirm that you accept the risks
- enjoy the few apps that still have developers motivated to develop for a user-base willing to put up with this