It depends. Some customers have concerns about Azure AD-joined devices because they need group policies or need Win32 app authentication. More details are needed to understand if it's a real blocker.
For apps, test them on an Azure AD-joined device. Typically only apps that require machine-based authentication won't work, and those aren't common. If the app works on a cloud domain-joined device, then you don't need to hybrid-join your devices because of that app.
For group policies, don't try to translate all of your existing group policy objects (GPOs) to Intune policies. For a cloud-managed device, there are some group policies that don't apply to the scenario. If you don't know why a group policy setting is configured, now is an opportunity to determine if it's still needed. Also make sure that you're not still using settings for an app that you no longer use. This process is an opportunity to optimize the performance and configuration requirements of your cloud-managed devices.
Use Microsoft policy analytics to help you understand if there are critical settings in your GPOs that you need to migrate to Intune. For more information, see Use group policy analytics.
Don't decide to invest in hybrid authentication only to avoid reviewing the settings that you need for your Windows 10 or later devices. Use this opportunity to invest the time now to be in a better position for the future. Also, a healthy and clean device configuration helps with performance and user experience. Don't buy new hardware, install the latest Windows version, and then apply an old configuration.