Do I have to provide the planned usage of my network to get a /22 of IPv4 address space

No. To obtain your one time /22 IPv4 allocation, you only have to confirm that you have plans to make assignment(s) from the allocation.

The RIPE NCC is allocating IPv4 address space from the last /8 according to section 5.1 of “IPv4 Address Allocation and Assignment Policies for the RIPE NCC Service Region”.