Too much sitting/remote job/Bikefit

I’m gonna start this with the (current) problem. When i sit on my bike and watch my front wheel, I “watch it” from the left side so i lean left. I have observed this recently. And why i mention sitting in the topic is because i have been working remotely for the last 6 months and i have done much more sitting. Yeah, i can’t be sure this is because of sitting, but that is the thing that has changed.

So how do i approach this? How do i know where in the body is the problem? Back? Glutes? Upper body? Could it be lack of stretching? Weak muscles overall? Hip?

Kinda hard to explain how my body is on the bike and english not being my native language makes it even harder.

Anyone else had a problems with too much sitting?