A language add-on, Tongues, can be set to automatically translate text with a chosen accent, as previously mentioned I think. Back when I still used the mod I personally found that it was overall better to just do accents myself if I’m going to do them at all, as automating it could yield results I didn’t intend. I’m not sure if Tongues is still supported.
There are three other solutions that come to mind, one being the also aforementioned act of toning down the accent. Personally I feel many rpers who portray accents for their characters tend to exaggerate said accent far beyond the in game examples. I doubt a portrayal slightly more subdued from the example given wouldn’t be too offensive to folks.
You could also simply declare the accent as being assumed, leaving others to translate normally typed text themselves. There’s a good chance folks won’t see such a declaration, especially depending on where you put it, and end up misinterpreting your apparent lack of accent. I imagine some might also just find it lazy. Either case isn’t really your problem, as I see it.
Finally you could try writing the accent out of your character entirely; that is making it so that having a typical Troll accent wouldn’t fit them. Obviously accents aren’t an inborn trait, so if this particular Troll, for whatever reason, wasn’t raised by or in the company of Trolls it stands to reason that they wouldn’t talk like one. This is merely one possible example.
As mentioned in a previous post you’re technically not obligated to do an accent at all. Personally I figure it might come off as odd for a character of a race with notable accent to not have one themselves, and I imagine there are others who might think the same, but that doesn’t make the former any less true.