Ai, gaming, defi catageoies are good to invest cause it seems altcoins which are related to such sectors, will have possible future. But nobody can ensure you anything. And now it already late cause market has pumped so hardl, btc is estimate 70k. before btc halving, it is possible for btc to revisit $35-40k, so that time will be good to buy. Some altcoins like Near, theta, fetch are from ai catageoy. Axs, egld from gaming catageoy. Link, inj could be good defi tokens. I can't say surely. Rather go to coinmarketcap and analysis more on these catageoy
Categories that you mentioned are all trend-based in my opinion, which means that some investors in the community hype them and that is the reason why some of the projects among these categories are making it in the list and gaining good momentum, however, for how long that momentum will last, it's unknown. That's why, I believe one shouldn't invest in trend-based coins or tokens because the gains will be limited.
One more thing, it is still not very late to invest in certain meme coins. When you look at some altcoins, they are moving rapidly even when Bitcoin is a bit stable, look at BNB, it keeps going up despite Bitcoin going sideways on certain days.