There has been mentioned suspension from TT as an alternative setup.
This is a rather costly route.
If OP decides that ESA does not fully satisfy his needs, allow me to suggest an alternative to TT.
https://www.wilbers.de/produkte/neueste-entwicklungen/archiv/bmw/bmw-r-1250-gs-adventure-2019/wilbers-fahrwerk-fuer-die-bmw-r-1250-gs-adventure-wilbers-fa.html
Wilbers shocks offers customized spring based on riders weight and load preference. The difference to the TT is that they reuse the electronics from the OEM ESA shocks, hence, the much lower price.
My 2c
This is a rather costly route.
If OP decides that ESA does not fully satisfy his needs, allow me to suggest an alternative to TT.
https://www.wilbers.de/produkte/neueste-entwicklungen/archiv/bmw/bmw-r-1250-gs-adventure-2019/wilbers-fahrwerk-fuer-die-bmw-r-1250-gs-adventure-wilbers-fa.html
Wilbers shocks offers customized spring based on riders weight and load preference. The difference to the TT is that they reuse the electronics from the OEM ESA shocks, hence, the much lower price.
My 2c