I haven't an answer for you - just wanted to make the observation; having voltage on a test point is no guarantee current is flowing through the circuit and for current to flow, at the other end of the circuit there must be a return, ground path or whatever.
There is a trend these days for power to be supplied to one end of a circuit and the switching or control elements to be at the other end. Commercial circuits are devious and it takes a fair amount of skill to test them and obtain meaningful results.
One problem a person has with testing a tv that is as much computer as tv, is many circuits have a level of intelligence for self protection - they sort of know if they aren't working right and can shut down. Modern thinking seems to be any lengths to prevent fire...
The Toshiba DVR620KU does not support dual-layer discs. See this page from ManualsLib, https://www.manualslib.com/manual/203807/Toshiba-Dvr620ku.html?page=9#manual . There is also a list of known compatible DVD discs for use with the recording function of the DVD rewriter/VCR on the next page. You should be able to dub a 2 hour (120 minute) tape to a DVD+R (4.7GB) disc. (I'll assume there is no copy protection on the tape.)
Look at page 50 and 51 for the directions for dubbing. Page 50 is here https://www.manualslib.com/manual/203807/Toshiba-Dvr620ku.html?page=50#manual . You'll want to focus on the directions in the left column. Note the section about auto-tracking of the VCR tape. Make sure to correctly indicate that the VCR is the source. Then after dubbing, finalize your disc to watch it on other DVD players.
I hope this helps.
Cindy Wells