At this point I'm less concerned with actors than I am with tone. Warner's mistake was trying to make the head guy of their MCU competitor be someone who felt Watchmen should be the tone of superhero stories in general, rather than recognising that it works as simply an alternate look at the concept. A Batman who kills, a Superman who begrudges saving people, a rush to get to the Justice League before doing the groundwork to make it matter....these were all mistakes and I think the actors themselves were far lower on the list of problems.
Warner especially now face a rare opportunity. The MCU is continuing but many are happy to consider Endgame an ending. If they actually do things right and if the MCU hasn't at this stage burned out public interest, DC could be perfectly placed to take the lead as a superhero cinematic universe.