5'10 isn't undersized for a CB...
2018 NFL draft has 6 CBs drafted in the first 4 rounds, none were over 6', only 2 were AT 6'. The 2 first round draft picks were 5'10 and 5'11.
Also, here's what I posted about the same topic last year:
Bandy, at 5'9 is the only undersized CB by NFL standards.