This may sound crazy, but imo Sony may need to go back to their roots. The one advantage Sony and Nintendo still has is Japanese games, niche or quirky stuff do not sell well on XBOX. It’s really working for Nintendo and gives them an identity and advantage. Maybe it will work for Sony as well.
Acquisitions might be pushing it, but form a very close partnership with Japanese companies and get genuine exclusives from TecmoKoei, Konami, Capcom, SquareEnix, From Software, Kojima, Namco-Bandai, Sega, etc. Provide extra funding if possible or necessary to give these games bigger budgets. Sure, these won’t upstage acquiring Activision, but there is still a big following for games from these companies. I know most of these games have the biggest player base on PlayStation anyway, but I think it could create some positive buzz for Sony.
Snagging games like Final Fantasy, Resident Evil, Silent Hill, Metal Gear, Dark Souls, Dragonquest, Street Fighter, Dead or Alive, Dragon-Ball, Naruto, Yakuza, Chrono Cross, Monster Hunter, Ninja Gaiden, Tekken, etc exclusively could give Sony a boost and give gamers another reason to invest into a PlayStation besides the first party games. For example, an exclusive Tekken 8 would probably turn heads especially since Tekken 7 hit over 8 million copies worldwide. Genres like JRPG, action, cinematic and fighting game fans are on PlayStation. Sony could and should take advantage of that.