You can, and it's trivial. I've never had a problem after a decade of constant use. My KeePassXC DB is synced between my phone, tablet, desktop, and laptop, and they all stay perfectly in sync. I've been scratching my head for this whole decade about why people want some SaaS for this.
The only use case I found (though still quite possible) is if I have NO access at all to any of my devices, and I only have access to internet, and precisely - web only. I could go to 1Password website (for example, in an internet cafe or via someone’s tablet), get into my vaults with the master key and the password, and start recovering other passwords, details etc. Without SaaS, it would be barely possible.