Pros, Concerns, and Ideas:
First the pros:
(1)Your product looks clean.
(2)Your heart is definitely in the right place.
(3)I really like what you wrote in your posts here.
(4)It sounds like an experienced team that is passionate.
Concerns:
(1) Apple's 180 on respecting a user's endpoint security and privacy this year.
(2) Security conscious users might soon start migrating away from Apple.
(3) Hitching your boat to Apple locks out the vast majority of potential users.
(4) The landscape of chat apps in 2021 is way different than when Skype came about... Discord is a beast that was built on just MariaDB after a few months of development time and scaled to 100 million users, using only a few terrabytes of data before doing a major re-write of the code switching to Cassandra NoSQL. Your users value privacy? Give them a private cloud and allow them the option of getting away from a provider that compromises their endpoints...
Ideas:
(1) Dark mode. Look at Discord, Microsoft Teams, Mattermost.
(2) Support for opensource, self-hosted clouds would give this app a reason to exist. Example -- Nextcloud integration or something as an alternative to iCloud...
(3) Maybe even sell the software as a completely self hosted, E2E thing using something akin to the OMEMO methods.
(4) Design / Designers could help with branding the product more.