Ubisoft said that even if as a public company they are forced to receive and review any acquisition offer, they don't want to sell, specially at a company that would affect their plans of supporting everyone and their creative freedom.
On top of that, even if they'd want to sell it would be better for them to wait a couple of years. They had a year or two without big releases due to covid and their roadmap, and starting this year they will start to release many big projects that have been under development for a while, so their revenue and value will go up for the next 2 or 3 fiscal years. It started with the low profile launch of Roller Champions but it should follow Mario x Rabbids 2, Avatar, the next Assasin's Creed and the next reboot of the series, Skull & Bones, the 3rd The Division (F2P), Rocksmith +, The Settlers reboot, Rainbow Six Mobile, Assassin's Creed VR and Splinter Cell VR, a few new IPs more, Prince of Persia remake and some games more. I have no idea about the BGE2 release date but I'd bet 2024.
FTC and the rest of regulators from the other countries won't stop the Activision Blizzard King and Bungie acquisitions because they are very far from having any monopoly, and even if they are top companies in the gaming industry they have a very small market share, slightly above 10%. And after these acquisitions are completed, same would happen if MS or Sony want to buy Ubisoft or a bigger publisher like EA or Take 2. No regulator would stop it.
Regulators are not going to influence who buys Sony next. What it's going to influence is if Sony thinks it's a great fit to buy them, if they are the best option available, if that company wants to sell, if they can buy it with their available budget and if they think it's the best moment to buy them. They may decide to wait to get a more favorable currency exchange, or because they think that the price of the company they want to buy will drop in a year or two, or simply they think that with the new PS+, upcoming H2 2022 exclusives like GoWR or Forspoken and early 2023 stuff like PSVR2 stuff and availability of console will keep have the hype high for a while, so may save the megaton hype card for later once the hype starts to go down and once the acquisition approvals and (this will take almost a year) total integration of Bungie is totally completed.
In the same way basically all Mojang, Bethesda, Activision Blizzard and Bungie games will continue being multiplatform, same would happen with Ubisoft if Sony or MS buys them.
They would make exclusive their marketing, appearance in game subs, bundles or betas/demos. And maybe would turn some games timed console exclusives for them. But all o almost games would continue multiplatform. Because their main goal by acquiring these publishers is to increase revenue, profit and market share plus securing stuff for their console and game subs.
Sony and MS are expanding to PC, mobile and (via these acquired 3rd party publishers) even the other consoles, and into other areas (VR, eSports, GaaS, game subs, cloud gaming, movies/tv shows/etc). AAA games become bigger every generation so they need more revenue sources. So Sony and MS aim for a way bigger pie, where that direct competition company represents a smaller portion of the total pie. Meaning that a console exclusivity has way less impact on that global plan and basiacally would only mean to earn less revenue and profit. And they want as much as revenue and profit as possible to reinvest it into continue growing.