Considering it was in that roadmap from 2020 or 2021 that leaked out during the ABK trial, Dishonored 3 is a definite possibility. However, since that was an older roadmap and we already heard that the Doom game from that roadmap never made it into full production, it is entirely possible that Dishonored 3 never got greenlit either. There is also the new post-credits Deathloop scene that got added alongside the Xbox port which seemed to tease a sequel to take into account, it's possible that Deathloop 2 got greenlit over Dishonored 3. However, considering both are technically in the same universe, maybe it could be both games at once, which I will talk about below.

Further discussion in a separate spoiler tag since I will talk about Deathloop's ending and some might not have played it yet.