I was trying to find any reference for controlling my (2019, 4K, 29" - can't remember exact model number).  I didn't see an immediate answer, so did a lot of looking and cross-referencing and figured it out. Figured I'd share it here for anyone else who needs it. 

For my Bolva I had Roku remote use brand Apex Digital, code 2. Works for me, hope it helps someone else.