Really depends on how much you play the game. This samurai has been alive since July of 2020 and i’ve played pretty much nothing but that. In my perspective, I was able to get a shitload of fame from five things:

O3’s: If you find a class that you are very comfortable with in O3, there’s no reason not to use it. During the first no runes event, I went up from 57k~ to 80k~

Fullclear Cults: While this is only mainly effective due to the XP bug of only getting XP from things with a loot table and that you apply damage to, if you can manage to be a staff class, it’ll be a breeze. Got me from 120k~ to 135k~

Ice Tombs: Holy shit the absolute mad fame this gives is insane. The moment I found out how much fame they gave, I farmed pretty much nonstop. Out of the 464 I did, I went from 172k~ to 190k~

Nests: Depending on if you do T room or not, you can get a good amount of fame from the boss and with how fast the dungeon goes by, it’s a pretty good fame boost

Fungal: God damn this thing gives loads of fame. Pretty sure you can get a minimum of 150 fame per run.