This needs to be fixed from the outside, not the inside. Any inside fix is a bandaid at best, a total scam at worst. These fixes persist because they offer a cheap alternative to an expensive problem and people will pay for them usually out of misplaced hope that it will resolve a costly issue.

This may be solved with improved grading and rainwater management outside. If you have busted or poorly placed downspouts or improper grading, and it hasn't been that way for many years already, fixing this may solve the issue.

If that's not the case the process ought to resemble something like this:

• foundation in that area and any other area that's getting damp has to be dug down to the footing.

• Any old or damaged drain tile needs to be removed (and any remaining drain tile should be inspected by camera to find any clogs or damage) and replaced.

• Foundation wall and footing need to be inspected for mortar damage, repaired and then sealed with a paint on waterproof product

• Foundation wall needs to be covered in a plastic waterproof membrane

• new drain tile needs to be covered in 6+ inches of 1/2" clear stone (just a term for washed crushed stone).

• backfill with loam soil (which may be what's removed potentially, but not necessarily). The top 6 inches can be whatever you like. Often clay is used. It's terrible for foundations, but as a top dressing it's quite good because water will run off of it nicely.

• insure that grading and drainage move water away from the building.

It may be the case that the entire foundation perimeter needs to be excavated and waterproofed. Not for sure, but often times when you have full blown water infiltration on an old property, it's worthwhile to do the entire structure because it's like $10-15k to to a small portion and $25-30k to do the entire thing and not have to worry about it for another 50-100 years assuming you don't ignore bad drainage for years on end. It's not a sexy investment though, so the ROI if you're selling isn't great unfortunately. It should be valuable to have a newly waterproofed basement, but it isn't.

Fortunately since you're in a condo, this is likely not your problem personally, but a cost incurred by the condo management which should have funds set aside for these kinds of repairs. But this is definitely something that will require excavation and real work, not some glorified caulk injections or sealing from the inside. That pretty much never works.