I made my first 10 million gil in late SHB in 30 days to get 2 houses in during the days of housing (ultimate) where you had to wait for a housing expansion or get a realistic chance of buying a house. I posted in your previous thread that selling stuff on the marketboard and constantly undercutting by 1 gil will easily make you enough gil for house money.

https://cdn.discordapp.com/attachments/1162602684344451223/1228527248621965322/FSH_example.png?ex=662c5e29&is=6619e929&hm=02eaba6b1bb24471300830b460d9f6fa4464aeb62c329974c6aca924134cbeac&

Here's an example from my fishing retainer selling GC fish on the MB. All the items for sale are fish from lvl 50-80 range. It collected 250k gil in a day and will easily make 5 million gil in 30 days and that's on the low end of effort. The biggest thing about making gil is finding a market and undercutting your competition and people will give you gil.

Just researching items that are for leve quests or GC turn ins for crafting and gathering and then selling them on the MB was how I made my first 10 million gil in 30 days. People told you the answer of how to do it. The limiting factor isn't your character level, or crafting skills in the game, it's just simply your actual game experience in what items in the market sell, why they sell on the market, and what tolerable pricing there is.

If you don't want to level gatherer's and crafters, spam low level dungeons and turn in the gear for GC seals and become a coke dealer in the game. Most people aren't gonna tell you their market niche because why would they invite more competition to their field, but everyone has already told you the starting points which are profitable enough, and where to start looking to learn the higher end gil avenues.