Historically, I think some of the longest swords were actually either ceremonial or anti-cavalry and anti-polearm infantry weapons that weren't used for actual fencing but used rather like a pike to stab horses or to chop the shafts of pikes.
Actually, Landsknecht (German mercenaries) where known to favour greatswords (Zweihanders) due to the nature of... Well, people are less likely to mess with a mercenary who's carrying around a huge ass sword. But there were some treatise made with explicit usage of greatswords, wherein they were used in a way that enabled good area control (Which would likely be another reason why they favoured it).
I've seen more references to greatswords being used in this fashion than any battlefield use, where 2 handed swords were less used (At least until the renaissance when full plate was used and thus shields were less necessary. But even then, it's still mostly Longswords rather than Greatswords)
I thought for a long while that the longswords my Tav and Laezel started with were greatswords.
Which would be the closest most media gets to accurately representing a longsword...
Since Longswords ARE in fact, 2 handed swords. Yet, very commonly video games use "Longsword" while referring to a single handed sword which is wholly inaccurate (At best you could sometimes lump Bastard Swords (AKA Hand-and-a-Half Swords) in with Longswords while being very reasonable to utilize in just one hand - Though they're still longer than most typical "Longswords" and always have that extended handle to accomodate 2 handed usage).
Thus you could consider BG3's "Longsword" to actually mean "Bastard Sword" (Though D&D itself has Bastard Swords as its own separate category, with older editions having them as an Exotic class weapon with a 1d10 damage die contrasting the "Longsword's" 1d8) at which point being large enough to 2 hand would be reasonable.
