So even a date could be hardcore to find
As I said above, with reasonable hardware and a correctly configured tokens file, btcrecover will be able to try every date from the last 100 years in one specific format in around 30 seconds. So even if you come up with multiple different ways to write out the date, this is trivial to brute force, provided it is just a date and nothing else.
Let's say you have "two thousand nine" and "two thousand and nine" for the year. 2 possibilities. For the day/month, you could have "January first", "January the first", "First January", or "First of January". 4 possibilities. You could put the year first, or the day/month first. 2 possibilities. 2*4*2 = 16, meaning you can try every date in the last 100 years with every combination of those possibilities in 8 minutes.
Even if you come up with 500 different possible formats to write the date, you can brute force them all in a few hours.