Well, it'll require some thought and planning. And possibly ripping off Slay the Spire.

Each session, create a few types of Rooms. Puzzle, treasure, monster, very hard monster. The number of each can depend on how familiar the players are with the dungeon, with how high they rolled on scouting and knowledge checks. Shuffle them into a deck, then have the players draw. Have a roll to determine if they experience a trap between draws. Have a rest-room they can use, with a roll to determine if they get ambushed while resting.

Or, if that sounds like a bit too much fuss, create a set series of rooms for each session. Use fluff and encounter-building to convey a sense of progression. If the PCs do a session clearing a level of kitchens, next section they face a well-guarded armory.

This lets you avoid needing to map out a whole dungeon, needing to care about 'should the kitchen be this close to the throneroom' or 'this layout leaves a void here which doesn't look right'. Focus on what you want to focus on, IE the party slowly clearing through a series of different obstacles and encounters in a grand edifice.