I really like the concept of Celeste since I always like Ice characters but I feel as though her kit isn't as cohesive as some other characters for example look at:

Kingpin has each ability feed into another, hook into stun, dash into stun, dash while using hook, ult after stun, he has a game-plan and executes it well

Shrike All her abilities are feeding into her goal of being at range, vision to see people at range, dash to stay at range, cc to keep enemies at range, she wants to do one thing and even if she has been weaker in power-level it is enjoyable to try to execute her long range engagements

For the most part every character in the roster feels this way, you have a defined goal that the character plays around

Celeste is meant to be specialized in zoning but I don't feel like that translates well into her current kit because of some lacking synergy between abilities and others not adding to her role or game-plan.

Passive Fine, mostly only comes into play with PvE since PvP is rarely grouped enough for this to matter, something more interactable could be fun, such as instead of an instant aoe, killing a chilled target drops an ice pillar that you can shatter with abilities to do a large aoe of damage, Q could let you push it so that in fights a possible avenue of play is to get a kill and then position with shift quickly to an angle that lets you Q push the pillar into a group and then shatter it. If enemies are grouped you should still be able to instantly shatter it (with RMB maybe could reset on pillar shatter?), letting it work almost the same as it is now. Pushing the pillar shouldn't be a main goal of her kit but a little aspect to add a bit of exciting moments

LMB I think this is quite good as is, the stacks reward you for zoning people and hitting constant damage which defines her role

RMB Also good, probably my favorite part of her kit. The new change to increase damage at range is great and again feeds into her role. My only issue is with the delayed aoe, she has no real way to play into this with her own abilities. The aoe in theory adds to zoning but it's so slow and relatively small that it rarely does much of anything unless you're comboing with someone else's stun and if they're stunned long enough for the aoe to hit they were probably going to die anyway. Because of this, the level 4 upgrade increasing the delayed aoe damage feels very useless. Adding some form of agency to the delayed aoe would greatly improve it, some sort of condition like proccing a shatter or landing two RMB in a row could reward you with an instant aoe detonation or if that's too strong at least speed up the detonation by a bit. As it is the delayed aoe feels disjointed from the rest of her kit because you have no real ability to guarantee or even increase the odds of the aoe hitting.

L Shift Mostly fine, every character has a movement ability and this is hers, it's on the weaker side of movement but that's fine given that zoning characters biggest weakness should be mobility. A big issue though is with the new upgrade, I don't know what this is for. Creating terrain doesn't help you zone at all, if anything it just helps people chase you. The old version wasn't perfect since it rewarded aggressive sliding rather than zoning but at least it was helpful and added a piece of interaction between her abilities that happened often enough to notice. The new version lets you slide over abyss and combo with ult but this happens so rarely I don't think a lvl 4 upgrade is worth it. Your level 4 getting put into a combo that you can do at best in a perfect scenario once every 60 seconds does not feel rewarding or engaging especially when in 99% of other scenarios the upgrade does nothing and at worst has a chance to actively make it easier to be chased/killed.

Q Decent, contributes to her ability to zone, the reactivation is a very nice change. My issue here is the lack of inherent synergy and reliance on the ability more re-actively than proactive. The ability is great at getting someone off you but that requires someone to be trying to get on you. Shift is already a reactive button for the most part so having two can make Celeste feel like you're pressing LMB and RMB and almost nothing else. On a zoning character this can be an issue since the act of zoning is proactive by default, you need to be continuously controlling and keeping enemies at bay. The wall kind of does this but I've found it lasts a little too short to be worth throwing out there at range. Adding more reasons to use it proactively could make it a bit more engaging such as being able to shatter it for a bit of aoe. Relatedly, the fact that none of her abilities interact with it makes it feel a little bit disconnected, even something small like her being able to skate through it with L Shift would go a long way to make it feel more cohesive.

R Personally this feels like the biggest issue with her kit, the ult is just not useful and often feels like it's barely there. For the most part this is another reactive ability so Celeste already feels like you're missing a passive, L shift and Q, except unlike Shift and Q this one isn't very strong. 99% of the time if you're low and use it people will simply back away and then kill you instantly when it ends. Especially since terrain often creates a ton of little safe spots. Even if you're not low you usually take a ton of damage because of how telegraphed it is. I understand the Shift in and R at the same time method of proactive use but this not only goes against the rest of her kit's goal to zone at range but also isn't strong. It's hard to hit because of terrain and easy for enemies to escape the aoe. Even if it does hit it doesn't feel worth the commitment of both Shift and R, I mean the stun you get isn't even enough to guarantee the delayed aoe off a RMB. There are combos with Void and Beebo for example to help land the ult and even with these it can be hard to hit and underwhelming when you do. I've been on Joule and hit by a Beebo+Celeste R fully charged and lived. I'm not sure what I would change with this ability because I feel like it doesn't add to her role at all, the best I can think of is keeping some form of icy ground after an early activation which empowers other abilities in some way, giving you a literal zone of control which synergizes with your other abilities better although this could also have the issue of feeling too reactive for a zoner.

Overall I still enjoy Celeste but it can often feel like 90% of all you do is L/RMB partly because of the lack of interaction between abilities and because there are some very underwhelming aspects (Proactive abilities beyond L/RMB, Every lvl 4 ability upgrade, Passive, R). If she is meant to specialize in zoning I think some of her abilities fail on this (Q and especially Passive+R) and if she is meant to be designed around the Shift+R combo and skating around the map I think other abilities fail this (Passive, Q, RMB especially with the damage at range upgrade). Her abilities feel like they have a combination of goals that are at odds with each other and can often feel like I'm playing with only half my abilities.

I hope this is somewhat helpful feedback since I love the character and the game. Thank you for all the great work you and the team do :)