@SkyyStorm Im flying the xfa-36a. It has an issue where you slow down, you literally have to fight with it so it doesnt veer to the left or right when taxiing as you slow down. Do you know which settings and where to alter them? Do you have an idea? This is not a wind condition. A configuration issue. The aircraft is still in development (beta stage) as well.
So I will start by noting that this is a beta (though I see there isn't even a cockpit, so probably more like alpha) add-on you are using, so of course there will be issues until the developer has fixed it. It might be a good idea to just wait for him/her to fix this, as any updates he does will overwrite anything you change manually.
They even have it under known issues:
Continue at own risk.
You are able to edit the steering via some of the contact points settings in the cfg file (flight_model.cfg) for the aircraft if I remember correctly. I checked some I remember. Either the castering is happening at too low a speed, or perhaps the rudder doesn't have enough ground steering control, which would imply the castering is at too a high speed. You'd have to experiment. There are loads of other settings that can cause drifting though, such as weight vs area, etc, so this might not fix your issue. I've never successfully edited those, its quite an art to get these right from scratch, especially if the plane is fictional, as then there's no references. But. Below some stuff you could play around with:
You can also modify certain rudder-related options under FLIGHT_TUNING to like rudder_effectiveness, if you also have trouble steering at higher speeds.
However, this is a lot easier to modify when doing it via the Aircraft editor in MSFS, but for that you'd need the source files, but that is not included in the add on files, as the developer has that with them (cause they are developing the aircraft).
I'm sure the developer will get to this issue eventually, they are aware of it.
And lastly, note that though you can change it for yourself, if you want to upload these changes, get the author of the addon's permission first.