Subtitles on vertical format video -

I'm showing a video based around a series of still photographs that that will be shown in a vertically oriented TV screen at a gallery. The timeline is 1920hx1080v with the vertically oriented images saved and imported with a 90 degree counter clockwise rotation. I've done this to avoid any resizing to maintain max resolution. There's a rough audio track backing the photographs and I want to create a subtitle track that will run along the bottom of the TV screen (ie. also rotated 90 degrees ccw to match the image) but, despite some research, haven't been able to find out how to do this (in fact some threads on this forum and others suggest it is not possible other than by using TEXT+ titles).
I have also created a version if the video with a 1080hx1920v oriented timeline but this shows on the (horizontally oriented) TV as a vertical video with black bars at the side (like a vertical video shot on a mobile phone). I don't want that - I need the video to show edge to edge on a vertical TV.
I've looked at a similar post (forum.blackmagicdesign.com/viewtopic.php?f=21&t=93441) but this centres on a problem with 4K and hasn't really helped me (as far as I understand anyway).
Can anyone suggest a way I can achieve my objective?
I'm using DaVinci Resolve 17.3.2 on a Windows 10 machine.
I have also created a version if the video with a 1080hx1920v oriented timeline but this shows on the (horizontally oriented) TV as a vertical video with black bars at the side (like a vertical video shot on a mobile phone). I don't want that - I need the video to show edge to edge on a vertical TV.
I've looked at a similar post (forum.blackmagicdesign.com/viewtopic.php?f=21&t=93441) but this centres on a problem with 4K and hasn't really helped me (as far as I understand anyway).
Can anyone suggest a way I can achieve my objective?
I'm using DaVinci Resolve 17.3.2 on a Windows 10 machine.