Recently, I came across a study Sustainable use of a smartphone and regulatory needs pleading for alternative OSes and mentioning Sailfish OS next to /e/ and lineage as one of those mobile OSes that are a true alternative to the two big ones. Here is an excerpt:
" 7.4 Alternative operating systems and custom ROMs
Sustainable operation can be improved by installing an alternative OS like a mobile Linux OS or a custom ROM for an android derivate, see Figure 3 (Maksutov et al., 2018). They are free of system trackers, fully functional and stable, as well as mature for daily customer and corporate use, compared with the case study of the European-developed SailfishOS as example (Grolleau, 2021)."
The study is worthwhile reading - even if you are not a SFOS fanboy