Larian hasn't been particularly huge on DLC in the past, at least by traditional means us gamers think of. Closest thing I can think of would be the gift bags for DoS2, which I wouldn't really say was DLC per se personally, as the original mods were already available on the workshop and nexus; Rather it was to port some of the more popular mods for console players to get in on a small portion of the modding fun too. Unless things have changed in partnership with WoTC, I'm much more inclined to suspect a definitive edition with more content and polished content based on how 1.0 went in player opinion, than extra modules added. (But it would be kinda cool to have post-content though, as long as it's additive and not cut out of the base game to be re-sold as "new content". But there's nothing imo to indicate Larian has gone down that dark path.)
Maybe because a DLC in DOS2 where you are already maxed out during the main campaign wouldn't make much sense, but given that BG3's max level will for sure not hit 20, the idea of waiting 5+ years to max out my character is not very pleasant.
Max level in the game code of Dos2 is 35 (though that is because of crashing due to an integer limit), though it doesn't follow PHB so any level cap there is arbitrary. I can also think of many other purposes of a DLC other than meeting a level cap. I'm only saying I find DLC unlikely, as Larian is in my opinion more into making a complete game for what it aims to do, to begin with. But who knows. I'm not opposed to seeing content all the way to max level in D&D
