Thanks. Then how would I use the result? Just convert the hex to another format?

Thanks everyone for the ideas. It is very helpful and jogging my memory.

I wonder how I would get started learning how to make a CUDA program that could create all possible permutations based on the current knowledge of characters, and the create the compressed or uncompressed private key and its address from which the balances could be checked against a publicly available list.

I wonder if GPT4 advanced analysis would help get started?

Great theories. Here is the exact format I wrote it in, but I changed all the characters. I do remember maybe converting it to hex or binary, or at least considering it.

0486 | 4AE5 | 41BC
A58F | 3FBA | 1AD7

34F6 | 2AEB
37A4 | 4AAF

7?A4 | ?42? | 6F?? | ??D8
71?D | 6?A? | ?FCA | 86B?

32?F
7F?B

It definitely has all the characteristics of hexadecimal. The question marks are sort of spread around the first half of the characters and aren't in the beginning or end. I'm sure I could read everything clearly when I wrote it down so I put the question marks there intentionally. All characters used in hexadecimal are located in the string of characters, so I didn't intentionally leave a specific character or two out and just add those in place of the question marks. I stacked they string of characters in a way I couldn't tell if it was two 40 character keys or an 80 character key. If I only use the top line I have a 40 character string with no question marks, but that is an odd length.

I read this in Armory's FAQ, and opposes some other things I've seen. What kind of key are they talking about here?
"Each bitcoin (or fragment of) belongs to a cryptographic private key, which is an 80-digit number that is essentially impossible to guess. Bitcoins cannot be transferred unless the holder of the private key uses it to create a digital signature authorizing the transaction. A Bitcoin address is a string of letters that let other users know what your digital signature looks like without revealing the private key (it is related to the “public key”)." https://www.bitcoinarmory.com/faq/

Thanks for the information. The public address starts with a 1 and here it is: 1DYFqhdKDkHYytVn66QWKGY4PUebNYH9j9

The character starts with most likely an A or 1, but read another way these are the first three 001.

I finally found the backup I wrote down after using Gavin Andresen's Bitcoin faucet. I don't remember if I was using only Bitcoin Core, Armory, or something like Multi-bit. Those sound familiar.

There are 5 bitcoins in the first address and I never moved or used them. The characters I found on my handwritten paper backup are 80 characters, between (0-9) and (A-F). I wrote these in blocks of four characters. Within these 80 characters, I have 14 question marks. So a total of 66 known characters. I'm not sure if I only need 64, 66, or 80 characters total.

I have Bitcoin Core and Electrs downloaded on my Umbrel to start trying the recovery process. I also have Electrum and Armory downloaded.

I'm not sure the best course to go from here to find out what the key may be and how long it should be. I'm not in a hurry and have time to try to figure this out, hopefully with your help.

Offering a full Bitcoin to the best helper.