All you need to do is change timeToTimecode to timeToCurrentFormat, like this:

L = thisComp.layer(“your layer”);
timeToCurrentFormat(L.sourceTime(time))

This is a very delayed response to your original post, but if Adobe hasn’t addressed this issue since 2018, I believe you could resolve it using the HDMI Instant Lock feature on the Blackmagic Design Mini Converter SDI to HDMI 6G – detailed here in this video:

I’ve found the best technique is to create a new adjustment layer above everything else in the comp and apply the Levels effect. This will clip only the highlights. Reduce the Input White value gradually and ensure the Output White value is identical to Input White. Keep reducing those two values until you achieve the desired result.