I'm just wondering if performance on PC will be worse than on consoles
I don´t believe so but it´s depending on your PC of course. I´ve a pretty decent one and I´m playing Bannerlord in 4k 60FPS (sometimes drops to ~45fps for a short moment in huge battles when armies clash) with all settings on max.
I don´t think that Ps5/Xbox Series X will be able to do the same.
Will probably the same as for many other games on those consoles, two options:
4k 30FPS (at best)
Full HD 60 FPS (at best)
But overall the graphics will be slightly worse than on PC but still looking good of course. At least Bannerlord was developed on PC as the lead platform as far as I know.
I also don´t believe in mods on the consoles, as far as I know TW would be responsible for them (have to test them so they don´t "harm" the console and stuff like this), I don´t think TW would just do this for free. That´s why there are just a few consoles games that offers some mods.
Everything that needs scripting is also not possible as it seems on console, I´m not aware of console mod that uses scripting in any way.
But maybe there will be more DLC than on PC, TW could offer stuff like different skins as mini dlcs on console while PC players could just use a mod for stuff like this.
Overall, I see no way that the console version will be superior to the PC version in any way. Console versions can only be better than PC versions when they´re the lead platform and when they don´t offer any modding. And that´s very rare.