Not really. Feudal society was a dangerous place to live in, unless you were part of the aristocracy or had some powerful friends. Even then, you were likely to participate in armed skirmishes. The middle ages life was hardly kind to anyone, but the MC is a vagabond, with absolutely no one to really stand up for him and thus immediately seen as easy prey for anyone interested. Such a person would also rutinely be seen as a fugitive (which is correct in his case) and therefore not deserving of any consideration. So yeah, him getting screwed left and right is pretty RL accurate.
Just to reply to this comment specifically, as I wrote in my prev comment:
1. This is a society with an unrealistic guild, such as an "adventurer's guild". A decentralized, state-recognized private militia, that promotes individual streghtening that rivals a noble's.
That goes beyond being a powerful mercenary group. It collects violent, potent individuals, offers them guidance, resources and some measure of protection, alongside prestige and an ID card to go around the world (as it seems).
No sane aristocrat would sanction such a thing, they'd desire to monopolize force all to themselves, they'd fear the obvious potential of: "Allowing "commoners" to powerup in levels and rankings".
Case-in-point: how can a bunch of random commoners access Rank-4 quests, that'd allow them to go beyond the ceiling of level 15, and thus venture into higher realms of personal might? Having relatively free access to the necessary weaponry, means commoners can threaten nobles, given talent, organization and time -- and the Adventurer's Guild motivates exactly just that.
The only thing missing, is a banking system, that is suspiciously missing from this story, and the fear of being constantly robbed goes the fuck away.
2. The MC DOES HAVE "powerful friends", or at least he should have.
He proved himself to be an extremely valuable, high-level adventurer. It is a complete contradiction that literally everyone BUT the adventurer's guild to recognize his worth.
In a sane story, that doesn't try to constantly force the MC to flee for his life in eternal conflict like some Chinese wuxia novel, the guild the MC registered with would rush to back him the fuck up, so they can maintain him as an asset.
TLDR: The appeal to history in this setting is futile, our reality and theirs are not the same on any level. It is a fantasy world that has the concept of empowering commoners with an "advenuter's guild". In a real world, you'd at best get a noble-sponsored merc group, or an opportunistic merc group that grew large from the spoils of war -- but it wouldn't be state-recognized, and it wouldn't be globally available, and they wouldn't fund, manage and channel requests for commoners and nobles alike.
And not to mention the whole "There are levels, skills and magic" shit, which this story tries so hard to pretend it doesn't have, which is nonsense on a whole other level, not to mention that it's BS that nobles do not block commoners from breaking the level 15 ceiling (i.e: enforcing a ban on selling black-steel weapons to anyone but nobles).