https://turbotax.intuit.com/tax-tools/tax-tips/Taxes-101/Can-You-Claim-Gambling-Losses-on-Your-Taxes-/INF14370.html
From what I understand, your allowed to claim gambling losses up to the amount the
amount of winnings within that particular year. I would 100% confirm this BEFORE doing
anything like this but I think at the VERY least you are safe to play up to the amount of tax
being withheld from your winnings.
For example, you hit for one million dollars and the IRS whacks you for 25% or 250K.
You would be allowed to "itemize" that 250K on your tax return meaning you are allowed
to claim up to 250K worth of gambling loses to offset that amount owed. In your case,
since you didn't really lose a lot before you hit big, it now becomes a race to gamble that
250K before the "time is up" which I believe is the end of the calendar year. Maybe someone
else can confirm that but I believe you are 100% safe to gamble up to AT LEAST the 250K
before the end of this year and write it off against your tax bill.
Now, please read that link I posted from turbo tax. There are VERY specific records you must keep
in order for the IRS to entertain allowing you to do this. You must have very detailed records and
receipts.
I believe you are able to gamble up to the full amount of winnings, to offset your tax bill, BUT
be careful. If your tax bill is only 150K, then it would be unwise to gamble any more than that.
Even though you won a million (or in your case 2.25 M) you can still only offset up to the amount
of tax you owe... the difference won't be carried over or paid back to you.
Long story short, gamble up to however much you think you'll owe in taxes... you can write it all
off and avoid all that tax as long as you keep the records in the manner the IRS requires.