I dont think its a mode / use problem, I used to have regular contacts with the USA east on 7 MHz using amtor , long back,
running round 240 watts carrier power , one guy even asked me 'which state liverpool was in' , unexpected dx ..
the new generation of data modes , reduced the power needs to something like 25 watts , a good + 10 db gain , to do the same thing
That was when the bands where in good condition , I do know from tests on 476 KHz , the latest vara HF modem is as sensitive
if not more so, than the slowest olivia mode , but many times faster and provides a amtor like fast turn round qso , using the chat module , interesting test with station 200 miles south of me , on MF