If you look at Havenstein's contract they clearly want him at RT through 2025 (age 33). At that point he could be one of the 3 or 4 longest tenured OL the Rams have ever had (in the mix with Slater, Smith, Saul, Harrah).
I agree that it could be disappointing to see Bruss entrenched as a backup (likely RT and RG). But it is what it is and you need quality OL backups- as we all saw a year ago... I also agree that the 104th pick in a Draft (even if he's the team's top selection) can't be seen as a "bust" unless he simply doesn't make the roster past year one.
The Rams want to feel good about their depth across the OL and I'd rather have a guy like Bruss on that right side- who again is very much still developing and in many ways still a rookie- than a lot of other options. Hope he gets a lot of valuable preseason work at RT.