Removing a concrete wall with home remedies

If a sledgehammer is not enough, rent a 30 kg demolition hammer, for example at Obi for 1 day with a chisel for less than €100. That thing (best with two people) will flatten it in 2-3 hours.
It's fun, don't forget ear protection.

We removed a similar wall on one side of the garage. The tools were a Hilti rotary hammer and an angle grinder with the appropriate disc. Making a few slots with the angle grinder helped us a lot.

Don't you know a bricklayer who can cut it off for you?