Do I have to provide the planned usage of my network to get a /22 of IPv4 address space
Yes. To obtain your one time /22 IPv4 allocation, you must demonstrate that you need the space and you must have already requested an IPv6 allocation.
The RIPE NCC has begun to allocate IPv4 address space from the last /8. This means that section 5.6 of “IPv4 Address Allocation and Assignment Policies for the RIPE NCC Service Region” is now in effect.