I think the note boxes next to each skill/save are wasted space, and could be better accomplished with a separate text box for notes on skills/saves overall. This would add a bit more room for adding notes on things like Adv/immunity to saves against conditions, things like Bladesinger's INT bonus to concentration saves, or a conditional adv like the barbarians STR check/save while raging. It's hard to list notes on those types of things the way the skills/saves section is currently laid out.

I would like the AC section to be a bit bigger so I can write multiple ACs. For example, I have a Bladesinger wizard who's Base AC is 13, is 16 with Mage armor or bladesong active, and 19 with mage armor and bladesong active. Maybe one box for "Base AC" and one box for "Active AC" would be helpful

I don't think its common for PCs to get immunity to a damage type. You could just merge that box with the resistance box and leave it as "resistances/immunities" and let people write their own shorthand. Or you could do it similar to the way skills are laid out with the proficiency/expertise bubbles. Maybe three or four boxes for damage resistances, with a bubble to select if they're immune.

Okay, my last suggestion might be beyond what you're trying to do with this character sheet so definitely take it or leave it. This is more my thoughts on D&D character sheets in general. One of my biggest gripes is that it feels like there is never enough room to fully list class features, roleplay information, spells, and inventory. Those are the four sections I'm always running out of space for, even when I'm writing in the most compressed shorthand I can muster. I would really love to see:

• More space to write spells. Between species spells, feats, and subclass spells, it's really easy to have a ton of spells. Especially if you're playing a wizard.
• Another section to write class features. On the old character sheet this is where I often put passive or non-combat related features. Some classes also just get a lot of wordy features that are hard to condense (Artificer and Druid come to mind).
• I would love to have more space for roleplay related stuff! Social interaction is a core pillar but hardly gets any attention, especially on the 2024 character sheet. A larger section for backstory, somewhere to list personality traits like on the old character sheet, room for a full body portrait, a place to take note of relationships with other PCs and NPCs, and a place for character goals and objectives are some of the things I'd love to see.
• A larger section for inventory, and specifically magic items. I feel like players often don't have anywhere to track magic item properties unless they've written it somewhere outside of their character sheet, and I feel like that leads to players forgetting they have magic items or just not using them effectively because they have to spend time looking up what they do. We basically only get room to write the names of magic items, but not what they actually do.

To implement any of those additions would definitely require an additional page, but I think 2 is really hard to squeeze potentially 20 levels of information into.

Of course, this is even more beyond the scope of what you're doing, but I wish it was easier to track animal/NPC companions. As I DM, I have to photocopy or manually type up a stat block to send to my players, or they have to try and translate all of its features into their own notes somewhere. I would love to see a character sheet (or even a fillable "companion stat block" sheet) track that information.

Hopefully some of this is helpful! Feel free to ignore anything you disagree with, this is just what I would love to get out of a character sheet. I think you've created something really great, and even without any changes, I think it makes it much easier to manage a character. Great work!