Checked my account cloud save history
and found save stopped in May despite I have been keep playing daily basis.
then suddenly could save started again today, over written my save,
lost all my progress since May. I was shocked hard seeing my buildings I spent a lot of time
just disappeared.
Found save files .old in local. too late I've already restarted game twice to see if it helps to recover.

Backup option maybe 5 or more generation would be helpful (not on steam)
or I will keep my saves rotated by myself (if I still can get motivation to continue playing)

asking steam support with little hope of recovery