Sounds like a combination of the lockdown restrictions, being away on tour, and loneliness have affected Phil's mental wellbeing to the point where he's made a poor decision.
There's actually a great film on the loneliness of fame and being alone in a foreign land called Lost In Translation.
In the film, Bill Murray's character is lost in the giant metropolis of Tokyo, wrestling with his fame and inner demons, and finds companionship and escape by courting Scarlett Johanssen's character.
Seeing the film from Murray's perspective, the audience gives little thought to the fact that he's a married man, and empathises with the very real, very troubling pitfalls of his situation.
I think it's a very modern tale that might just give a bit more context to Phil's actions.