This is not a tutorial or a guide. This is just something I found that works for the black screen issue (for me). The only thing I can say is that it works for the GPD XD Plus on my 4k TV.
For those of you that are more tech savy and have a full explanation as to why the XD Plus acts up, please let me know. Anyone that finds other ways to remedy this, please let me know in the comments.
This is the adapter that I use: https://www.aliexpress.com/item/32874590699.html
If you do not mind the wait, then Aliexpress is the way to go. If you would like it in a few days and live in USA, let me know. I have some for sale. $12 USD ( shipping included ) Contact me here: https://redd.it/b3hl9f
If this also works for your TV please let me know.