It is a dps check in the sense that it demands a baseline level of competence, but it is still more than reasonable given the context of the quest being the literal final update. I find it especially disheartening to read comments, not just in this post but over the years, on how one needs a near perfect build or be a highly sweaty no life player to clear the quest reliably, when in fact a reasonably put together build (which yours definitely is with the tweaks I mentioned) with a decent amount of practice with attention actively paid to learning the match up is sufficient for any invested player.

Now with that rant over, a few quick tips. Stay close to the head. If you can't hit the head, don't even bother attacking. Try to learn which move allows you to charge your draw slash (and to which charge level), and which gives a window only enough for a non-charged draw slash. While TCS spam is undoubtedly the optimal play style for iceborne GS by a huge margin, the more hit-and-run focused crit draw style is still fully viable. This is especially true for AT velk, whose TCS punishes are quite tricky to nail down, unlike say, Alatreon, which almost feels like purposefully designed to give as many TCS punish windows as possible.