Although, if you turn it off on the drone, it will not generate an SRT file with telemetry, which you may want for some reason in the future.
The SRT files are small compared to media, so they don't meaningfully impact recording space.
It's easy to just turn off subtitles on the TV, that's what I'd recommend.
Or, creat a subfolder and put all the SRTs in there... they have the same name as the video files, so easy to use if you need to.
I've occasionally used the SRT overlay to see altitude info in some part of a flight where it was important to me.