Okay, I see, your “Device Manager” is the same as the newer “Device Care” I was talking about. I have found a forum post on Samsung’s main page where someone had a similar problem and they fixed it by factory resting their TV, which you could try and if it works then your all set to go (Solved: Recent Update to SmartThings broke the remote cont... - Samsung Community - 2488842).
I really think though is you have ran into the problem I have with my oldest TV (2017 model) is that your TV in layman’s terms is too old for the newest version of SmartThings and is no longer supported, so the remote features will no longer work within the app. I know older models are no longer in Smartthings and according to JDRoberts a highly respected and knowledgable forum member; models from 2018 and older are no longer supported and this decision was made last year as seen in his forum post here: (Is Samsung SmartThings Discontinued? (Jan 2024) - #2 by JDRoberts).
Also I’m not sure what model you have as there are two different 7 series that I can think of (three to be exact); the 7 series flat QLED, 7 series curved QLED (Which I had and died, also it wasn’t supported anymore in SmartThings and was identical to the flat model except the screen was curved) and many UHD Crystral display 7 series. All 3 of these seem to be 2018 or older to me and wouldn’t be supported anymore.
I could be wrong that other models exist, but I’m unaware of them and can’t narrow down your model year without the full model code.