What do you do when clients are not able to specify what they exactly want? Do we present them with one or more possible solutions?

Continue billing them until they figure it out or stop paying.

Make proposals and make it clear that you can't start before you agree on what it is you're making, and bill them for this process.

No need to make a stink about it, sometimes it's not obvious to them how specific you need it, but what you need to avoid at all costs is the "idk whatever, you figure it out", then spend two months on a thing before they go "not that tho".

Present their mess back to them, bill them for it, and await for a "oh, that's not what we wanted" before starting any work.

talk with them until we figure it out together.

bill them for the time, of course.

if they complain that "you're not doing any work, just talking with them", tell them that it would cost at least 10times as much $ and take at least 10times as much time to be redoing the thing until they finally figure out what the hell did they want in the first place.

use house building metaphor: "before you can even start drawing the blueprints you need to know how many bedrooms, bathrooms, floors, etc. so we're talking until we figure that out. then i'll start drawing plans and building the house"

Many people can’t describe what they want before they see something to talk about in terms of ”I like it but a bit smaller type would be good”

Many designers argue you should pitch the client 3 sample options.
4 can feel overwhelming.
2 feels like if you dismiss one you’re forced into taking the other by default.
With 3 you have a small but sufficient amount of choice.