HoMM3 HD is a mod (add-on) for the game Heroes of Might and Magic 3.

baratorch, can you tell me which settings control autosaves?

starting from version 3.806
HD3_Launcher.exe - Main Settings - Save every day (for tournaments)

or you can: HD3_Launcher.exe - Tweaks - < Misc.TournamentSaver >

for the 20th time, there's a request to remove the reset of settings upon update

Settings are reset only when there is a significant change in the structure and form of storing these settings. I will not write code for each new version with such significant changes, which will iterate through all old formats in search of the desired installed option value - this is a hassle and will add a very large, confusing, non-universal, and ugly piece of code, sorry.
There were also cases when settings were reset due to my mistakes, but I cannot guarantee that I will not make mistakes again.

Regarding the transfer of old settings to the update, starting from some 3.8?? version, everything has become much better than in all previous versions.
When updating from 3.806 -> 3.807 -> 3.808, the settings definitely do not reset. And in the foreseeable future, there are no plans for radical changes in their structure.