Miscellaneous topics that do not fit into specific categories.
Unfortunately you'd need to purchase a full, new standalone license or a subscription because AFAIK Microsoft does not offer a direct, discounted upgrade path from Office Home & Student 2019 to Office Home 2021 or Office Home 2024.
Perpetual, one-time-purchase licenses such as Office 2019 do not convert or receive a discounted upgrade to newer perpetual versions. You need to purchase a brand-new standalone license, such as Office Home 2024, or sign up for a Microsoft 365 subscription.
Your old Office 2019 product key does not automatically convert or upgrade. If you purchase Office 2024 or Office 2021, you receive a new product key or digital license that you redeem and associate with your Microsoft Account.
Installing a new version of Office will not delete your existing local Word, Excel, or PowerPoint documents. As a precaution, , you should back up any important local files and custom templates before beginning the installation.
To transition to the new version, first go to your Microsoft account page and redeem the new Office 2021 or 2024 product key or license. Then run the Office installer. In most cases, the installation process detects the older Office 2019 installation and removes it as part of the transition. After installation, open an Office application such as Word and sign in with your Microsoft Account to complete activation.
More at https://learn.microsoft.com/en-us/answers/questions/5961786/procedure-to-update-from-2019-to-2024 and https://support.microsoft.com/en-us/office/lifecycle/officeinstall/how-do-i-upgrade-office
If the above response helps answer your question, remember to "Accept Answer" so that others in the community facing similar issues can easily find the solution. Your contribution is highly appreciated.
hth
Marcin