No, I wouldn't want to read a 5k long bio.
I'd think 1,200-1,500 chars would suffice..max. The thing is, many people like using color codes (myself being one of them). I don't just randomly stick in color codes and make it look like a giant bowl of fruitloops, but I use a good amount. Using more than a few forces your bio to become smaller and smaller.
A lot of people who used this bug used a layout like this (an example) because it looks nice, organized, and resembles the rest of the bio:
`n `^Home Village: `lK`Lirigakure
`n `^Chakra Affinity: `2F`@uuto`2n
..and so on. With this layout, you aren't really making a long list or even using that many colors, but it still literally takes up dozens of chars for so little. I think in the small 2 lines I provided above, I have 50+ chars. Increasing the chars to 1,200-1,500 would make it so you are using 800-1,000 chars (letters) plus all the codes involved.