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 must confirm that you have plans to make assignment(s) from the allocation and you must have already requested an IPv6 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”.