Whether al-Shifa hospital etc. host Hamas weapons and tunnels is under current dispute. However these are not new claims by the Israelis. For years and through multiple rounds of the conflict they've said Hamas deliberately hides in populated civilian infrastructure - mosques, schools, hospitals, ambulances, private residences, etc.
For example, a 2009 post from the Amit Intelligence Center:
The many mosques in the Gaza Strip serve not only religious functions, but are also put to military use by Hamas and the other terrorist organizations. They are used to hide terrorist operatives, store weapons, as sites from which rockets and mortar shells are launched, sites for launching terrorist attacks and for training terrorist operatives.
Is there any verified evidence from before Oct. 7, 2023 that Hamas has used active civilian infrastructure for military functions?