You just need to clarify when you actually get the bonus. Because there's two types:

1. You get the money in the next paycheck or two. It's a "Thank you for not quitting on us" gesture of good will with no strings attached.
2. You get the money one year from now (in Oct 2023) so you have to stay on the job for another year until you get the money. This is much more common for "retention" bonuses and why you found this type more often when you did your Googling. Often the timeline is actually spread out over multiple years so you get 1/3 after one year, another 1/3 the 2nd year, and the last 1/3 the 3rd year but it can vary drastically so you'd just have to check with your boss. I have had 1-year get-it-all retention bonuses like this, but is just more rare.

Both are very normal business practices to retain employees and keep them happy. I've gotten both types in my career.

Since it's only $5k and he said it was "no strings attached" then it's probably the first type but just talk to him and clarify it.