The best way to describe my stance on the topic is probably this: moving between different social strata always generated intense hatred in medieval societies (which FR is based on). Nouveau riche are generally despised everywhere, and by everyone. An Urchin who bought themselves into a noble district will have lots of tension with their neighbours. Similarly, a Noble who lost their fortune and now has to (somehow!) live alongside paupers, will be equally loathed (by both their neighbours and other nobles).
If Larian is smart, they can use this aspect to add a twist to Tav's story once we reach Baldur's Gate. That would be tremendous. However, I don't see them to be particularly interested in creating a deep, complex storyline for our custom character.
I mean, have you read any FR novels? Adventurers are not upstarts, they are a vital neccessity that are generally accepted by all social strata. Kings and kingdoms don't always love adventurers wandering around getting into trouble, but even Cormyr, one ot the strictest kingdoms in regards to adventurers, simply put limitations on them. When some random group of adventurers appears out of the nowhere and saves the day once, it's a fluke, but when it happens regularly, which it does in the Realms, then it becomes an institution. It also helps when said random adventurer may very well be an arch mage or other high level class. A level 12 warrior doesn't get spit on in the slums, they get avoided or catered to, regardless of what social strata they originated from, an urchin who becomes an arch mage is an arch mage, and his origins no longer matter, because that arch mage can single handedly repell an invasion. Sure, in the low and mid levels there can be some tension, even in the high levels there may be whispers and cold shoulders, but the thing about high level characters is that they can litterally crush armies as a party and drive dragons into their enemies. Wealth and status are a type of power, but real power garners wealth and status.
It should also be pointed out that your character isn't the first adventurer to walk the land. The path he walks has been paved by those who walked it before him. There are many many powerful people who have created organizations that look out for adventurers as a whole politically because they see them as a vital resource in culling back the darkness and in providing early warning for potential calamyties. It should also be pointed out that several of the gods, in the FR were previously adventurers themselves, and as such, the temples generally favor adventurers of like alignment, or now I suppose I should say temperment.
