4a is almost around the corner, with new Pokémons announced today, I expect first “leaks” or official teasers later this month and a launch next month.
Besides the NP3 will likely remain the flagship phone. We’ll see how Nothing handles the 4a and 4a Pro this year, I expect both of them to be more expensive than their 3a counterparts but less expensive than (discounted) NP3.
So getting a Nothing Phone 3 is always a safe bet, however if you aren’t in a hurry, you might as well just wait on how the 4a series will turn out.