It took me around 50-60 hours to get 10+k coins.
Uhhhhh, you're doing something very wrong if Charons are that hard for you to come by.
Ya its called I wipe the merchants out every restock with one expensive sale.
The reason it takes so long is cause im waiting on them to get more damn money.
Also I spent maybe 10k on the house (crafting/one security upgrade and all floors renovated) before checking the wiki to realize even the security system was pointless...SO you know, great feeling to have to check the wiki for every decision or anything involving choice/money since the game has a lot of "LOL fuck you" moments. Or just down right "out of left field" moments. I don't like being scammed, the decor, sure, its decor, but the multiple levels of renovating and the security system being pointless (unless its used in the point of no return) then ya, dumb.
Also I am basing this off vanilla underrail I only started expedition so if there is some huge revenue that opens up then ok.
I would say its not a stretch to say the average player has around 8-15k coins when they start the expedition soooooo unless you want to give out some kind of "secret" that nets you tens of thousands of coins easily; aside from the obvious mercantile point investment or some min max drivel I am calling you out.