I have the note 8 and using it with T-Mobile in the SF bay area, my phone never shows "4g+". Most of the time it shows as "4GLTE or 4G" depends on the location. when it shows "4G (HSPA+), i would manually turn off the data, and turn it back on so it can connect with 4GLTE.
i have TMobile in San Francisco. Funny, it always shows 4G and Never 4GLTE