Navigating Microsoft Office 2019 Support and Subscription Concerns

As you mentioned, Microsoft Office home and student 2019 is indeed a perpetual license, which means that you can continue to use the software even after the end of mainstream support in 2023, with some limitations. During the extended support period, you will still receive security updates, but you will not receive any new features or non-security updates.
It is important to note that Microsoft has been shifting its focus towards its subscription model, Microsoft 365, which offers additional features and benefits, such as cloud storage and collaboration tools. However, it is not mandatory to switch to a subscription model to use Microsoft Office.
If you do not want to switch to a subscription model, one option is to consider upgrading to the latest version of Microsoft Office when it becomes available. This will ensure that you have the latest features and updates, and will also reset the support period. Another option is to continue using Microsoft Office home and student 2019 after the end of mainstream support, while keeping in mind that you will no longer receive non-security updates.
Alternatively, you can explore other free and open-source alternatives to Microsoft Office, such as Apache OpenOffice or Google Docs. These alternatives may not have all the same features as Microsoft Office, but they can still be effective for basic tasks and may be a good fit for your specific needs.
Ultimately, the decision of whether to upgrade or continue using your current version of Microsoft Office depends on your specific needs and preferences. However, it is important to keep in mind that there are still alternatives available if you do not want to switch to a subscription model.