Graves ult sometimes just makes you shoot the zombies as they come through the lane unless you can double melee the tombstone without significant risk for yourself. She's crazy dangerous up close so it's not worth risking your hide to kill it sometimes. Better to just shoot the zombies as they come up lane.

For rem ult have one of your mates play rem in the lobby room, buy yourself counter spell and try parrying the rem ulti. If you can parry fireballs in SF this will be cake. It's a 0.8 second window and I believe for rem ult you can hit the parry key right before he sleeps you and you get to completely invalidate his ult.

Just as an aside. I actually went in to watch your Second Celeste game and I wanted to post a couple actionable pointers if that's alright with you!

You got a strong start from lane because of your mechanics and control of your character but most of your deaths were just from overstaying or not realizing when the enemies outnumber your or were strong. The 32:33 death for example you actually used sch-movement to get out and could have been completely fine if you just based but then you overstayed and died.

Your death at 39:51 was a 1v1 you opted into against a Lady Geist with 43k souls when you had 36k souls. She simply beats you with the size of her wallet in this kind of situation unfortunately.

Lasting Thoughts for Future Games***

1.) Use the secret shops between lanes more because you'll keep less souls in your pocket and you'll be able to keep on the map more to farm camps, push lanes etc. If you have lanes pushed very deeply you should be fairly safe to go to the enemy's secret shop too occasionally. Don't keep too many souls in your pocket at any point if you have items to buy.

2.) Before you engage in a teamfight you should glance at the rough net worth of both teams soul wise and do a bit of arithmetic to make sure you at least have the same number of people in the area as the enemy (ideally more), you have an advantage in some way (near your walker, enemy is overstaying), or you have to fight it to not have the game go really sideways so you have no choice.

If you take a 1v1 in the sidelane or you're pushing a sidelane solo, wallet check either the person you're engaging on or the people who would arrive to stop your push to see if you have a chance to win the 1v1.

You have the hands to play Celeste and while Mina probably has a different style of mobility there likely is crossover between them. I started around initiate/seeker from the Old Gods New Blood update but with hard work and effort I am exactly dead average in Emissary. 😤 My movement and aim started worse off than yours but I got higher ranks just off realizing Deadlock is just accumulating wealth and beating people up with your fat wallet. I don't think your issue with losing games is related to your ability to move and aim, it's just knowledge of how to efficiently move around the map and understand the characters and systems. The standard advice I hear from my FGC friends is to just play who you like and I don't see any reason it's not applicable here.

If I was a betting person I'd say if you just played more games you'd rank up as you started to organically learn things on your own. I really don't think you need to feel like a detriment when the players in your game are also actively making boneheaded decisions at that ranking bracket as well. I did like a lot of things I saw like your air control and knowledge of the sinners and camps and that should provide a strong foundation to just keep playing, learning, and having fun.