>>24062
NTA but yes, it does get pretty trivial quickly. After not playing UT since release it took me up to 30 whole minutes to beat him the first time on the proxy, but after that it's been really smooth sailing. I did the fight ~15 times since then and I've only lost twice due to getting too cocky and trying a healless attempt too early. And it gets easier past that, too. The attacks are all fair once you recognize them, and a fun quirk is that Sans will start with a weaker version of the attack he's showing you. One attack only reaches full strength on its third occurrence. imo Phase 2 "buffed" lasers are way more free than their introductory version, but that's subjective.
Because of this and also to save time, try to avoid healing unless you're either between phases or right before his final attack (you can count to 10, or you can read the text like a scrub—"Sans is getting ready to use his special attack"—that's what I do). You can tank a huge part of his final attack before you figure it out since the final slams are just for show—they can't kill you.
The fight takes ~5 minutes once you can do it consistently, and it's an easier task than it seems. One small time save is skipping phase 2 heal, but only do that once you get comfortable with his final barrage.
>the blue bone
The first phase attack with sliding small bones followed by tall blues? See attached video. That one's imo the second hardest after the wall smashing in phase two (only on the third+ time he shows this; you won't see it at all in many fights). Make really tiny jumps while going a bit in the bone's direction once you clear the blue, except for when they change directions because then you can dodge two with one jump. There is a delay before you start falling, but the heart stops its ascent immediately after you let go of the button. Your hitbox is a tiny dot, not the full heart, see picrel.
If you meant another attack, here's the full fight:
https://files.catbox.moe/ouppkg.mp4
Awful attempt with a panic heal to boot, but I can claim I was being bad on purpose to show that everyone can do it. I'm not rerecording it just to look better in a forgotten bunker thread of a vietnameese goat herding forum, lol.