It’s possible to earn this amount by farming old world mats but it’ll take you some time.
Grab mining and herbalism on a druid above lvl 100 and fly around the Cata zones. Mine everything in sight (focus on obsidium and pyrite, elementium is barely worth anything) and herbs. The Cata herbs sell for nearly 4 times more than the usual BFA herbs.
If you’ve put a bunch of cata mats on the AH and it didn’t sell yet, diversify yourself by farming other mats (I’d suggest Legion ore & herbs > Wotlk ore > BC ore & herbs > Mop ore) as just focusing on a few items could be a disaster for you (one angry competitor and all your time will be wasted)
Here’s a cool “guide” (well more like personnal experience from someone who does a gold farming challenging with gathering prof) i really suggest you read it.
https://www.reddit.com/r/woweconomy/comments/etq60a/brutosaur_challenge_with_gather_professions_day/
Edit : Another challenge from the same player but from a classic player perspective with no gold making experience and with but a lvl 110 character over a month
https://www.reddit.com/r/woweconomy/comments/cjgaae/1month_wow_token_challenge_results_12_million/
These farm work, but are not optimal.
You can also try the raw gold farms if you have multiple 110 characters :
https://www.dataforazeroth.com/calculator
It’s really time consumming but it will work for any server. If your AH is dead then this may be your last hope
The easiest option for BFA would be to farm herbs but it’ll require flying to be efficient and you don’t have enough time to get pathfinder.
I’d suggest either to levelup a DH, gear him with catchup gear and farm leather. It does not require flying and you can expect to get a token in about 10~15h of farm if you do it seriousely.
For instance with 450ilvl gear and all the additional systems you have in BFA i get about 25k gold per hour farming snapdragons in Nazjatar for dredged leather (about 20g each on my server) and cooking (bil’tong requires 0.8 of the meat you get from the snapdragons each and sell for about 50g on my server). Got my hands on slightly more than 600 leather and 100 meat in 30min of killing everything in sight altho it could be much higher if there were more players around (increase the spawn rate)
Once again it’s extremely server depandant. It works on mine because it has an active raiding community but without it the leather would be worthless.
Hardly sell on my server altho very profitable. Unless there’s a lot of competition and folks keep on relisting after i post my stuff which is also possible