The HTC U12+ was launched back in 2018 just like the Samsung Galaxy S9 and Huawei P20 Pro. While the S9 and P20 Pro have received the Android 10 update, the HTC U12+ remains stuck on Android Pie, and its prospects of getting Android 10 remain virtually non-existent.
https://www.notebookcheck.net/The-HTC-U12-remains-on-Pie-two-years-after-launch-and-Android-10-remains-but-a-dream.463690.0.html