Hello, finally I found a solution. I want to thank @RenaudLN. The post in Format ticks : add 'km' at the end reminded me of the possibility to use prefixes and suffixes. The following code solved my issue
tick_Sett_Y = {
"tickprefix": r"$" ,
"ticksuffix": r"$",
}
tick_Coll["yaxis1"] = tick_Sett_Y.copy()
# apply changes
fig.update_layout(tick_Coll)