Most D7/MI/CPLP folks from the 2021-24 cohort would already have a residency card in hand (since they were all prioritised before GV applicants for, cough, moral reasons). They can just mail in citizenship applications by themselves just in case it works, without paying any attorney fees.
If they fill in the current residency card’s info (card #, valid from, valid to), and don’t submit the CdT, then IRN will not know if 5 years have been clocked until AIMA responds to whatever inquiries from IRN, which could take years. So short of some form of penalty from IRN (e.g. rejection citing bad faith + no new application for 2 years), there is very little downside.