If you have 100 mil you can at least triple that in 5 days. It would be up to you to do the arithmetic for how long to get one month’s PLEX. Although, you might hit supply / demand issues long before then.
Quoting from myself on previous question on how to best invest 60 mil (my suggestion was to buy and trade ice):
Above was based on around 243 k buy price + 2.5% brokers fee and selling for around 304 k. You can currently buy the same flavor of ice for around 229 k and sell for 284. Once you get above 2 - 3 000 units per day however you would start to hit supply issues. But then you could perhaps move on to another commodity or buy from more than one ice system? The trick would be working out how to transport your ice to market to keep your cash generation fluid.