PS5 has nothing to do with this. MS doesn't care about Sony. No MS meeting begins or ends with "What's Sony doing?" Until Sony builds infrastructure like Amazon and Google, MS could care less about a company with a market cap smaller than some divisions at Microsoft.
MS is a subscription company. They sell subscriptions to stuff. They aren't interested in selling people one off games or software. They want money from consumers on a continuous stream. It's called Annual Recurring Revenue. The CEOs pay is even based on how many subscriptions the company sells.
So you people need to end this fantasy now. Seriously. If you have any doubt on what MS next step is on anything in the future, just ask yourself one thing: "Will it sell GamePass subscriptions?" So let's try this one. Will releasing Bethesda games on Playstation 5 sell more GamePass subscriptions? There's your answer.
Now if you want to speculate that MS will release GamePass on Playstation 5, go for it. That wouldn't be unprecedented. They release Office apps on Mac, iOS and Android.