As rigmarole mentioned, you are going to have to get rid of (or turn off) a bunch of plugins to find out if they are causing the lock-up on iPad.
One benefit of using iCloud sync is you can make changes on your mac and they get synced out to all other devices (easier than dealing with the iOS/iPadOS Files app). One drawback is that you can’t have selective sync of settings like Obsidian Sync. Unless something has changed recently, by default, it’s all or nothing for iCloud sync.
When I used iCloud only, I had separate config directories for desktop and mobile, .obsidian and .obsidian.mobile, because settings kept getting messed up between the two. This keeps settings/plugins/etc from desktop and mobile apart. This may be a pro or con for you.
30~40 plugins is probably fine on desktop, but I would never run that many on mobile (right now I have 7). YMMV. You can create the separate config folder in Settings > About and choose the one Obsidian uses there. iCloud will sync any number of them.
Another option that I haven’t tried is selective iCloud Sync → Exclude individual file in shared .obsidian settings folder from iCloud sync