Have you seen the location of Belgium on the map? have you seen the location of Ireland on the map? Are you aware of the fact that corona virus limited international travel in 2020. Are you aware that as of sept 2 larian said they finally finished recording all the voiced lines for EA? Given the state of the world is it really unreasonable that the access to English speakers was limited to those with an "English" accent?
20 years ago, absolutely that would be an excuse and I wouldn't even have brought it up.
In a world where high quality recording devices can readily be shipped around the world, even in Corona virus impacted areas, and the internet exists....yeah, not a valid excuse. All the more so because there isn't even an Irish accent in the game. Nor Belgian.
Maybe let’s revisit this again later into EA. Not saying the OP shouldn’t bring it up, I am British and even I don't just want the same accent, but on the flip side you do want similarity for regions, but yeah aren’t the Githyanki from a different plane (fuzzy memory), shouldn’t their accent be different?
You do have to be cautious that you don’t fall into stereotypes though, dwarves with Scottish accents, characters with certain skin color having voices matching real world locations for example.
That's my worry though, is that Voice Over work is probably the greatest investment of time and effort besides the actual programming of the game. What we are seeing is all of Act 1, as the voice over work exists right now. Delaying until later makes it that much less likely that Larian will invest the time and effort to record new voices, because it takes time.
We know they are willing to redo voice over work, just look at how they removed the passive voice for the narrator.
Voice over work artists are talented people. While I hate to reference it, just look at Critical Role and all the different accents that are capable from just 1 artist. You don't even have to have characters/races be stereotyped to one accent (Dwarves being Scottish as you noted), just give them instructions to not use the exact same shortened phrases, tones, enunciation, etc. (all the factors that are typically defined as an 'accent') for each voice like there is now.