Use iMac 2017 as monitor for MacBook Pro 202 M2
Can I use iMac 2017 as monitor for MacBook Pro M2?
iMac 21.5″ 4K, macOS 12.2
Refer to Use your iMac as a display with target display mode - Apple Support.
Only certain models are eligible to use Target Display Mode and those Macs are not among them.
It's no substitute for TDM but you can use Screen Sharing: Share the screen of another Mac - Apple Support.