Zardnaar
Legend
There is no way for a party of standard point buy 7th level PCs that those encounters are 'easy'. They all present a moderate resource drain that should (by the time the 7th encounter is triggered) have them very low on spells and resources indeed.
The Remoraz alone deals over 50 damage at +11 to hit with swallow whole (has 200 odd HP at AC 17), and they have to fight that after dealing with 6 encounters, including with a mage (with fireball and counter spell), a dragon (breath weapon and flight), several orcs (including a caster), ettins, displacer beasts etc.
Assuming you run the encounters appropriately.
You describe the Remoraz bursting out of the ground and roaring, you place the miniature 20' away from them on the board and say 'roll initiative'. On its turn it moves to a PC and eats him or her.
7th level clerics fully healed are on what... (assuming Con 12) 45 HP at an AC of 18ish? Barring some pretty cruddy luck, it eats a PC each turn. Its immune to fireball.
In my games (with very experienced players and optimised PCs) they would be challenged.
Am I missing something here? Whats the magic item load out on this group, and are you letting them roll stats?
That's was default array. Last remorahaz we fought we fought I think my monk shut it down with sentinel and the kids thing granting disadvantage.
They are not immune to the blindness spell either or hypnotic pattern.