I don't think you can redirect, using regex, however, A solution for individual redirects can be achieved. This has been explained here, for safe search.
for your redirect, this would imply this hosts (/etc/hosts) entry:
172.217.17.36 googlevideo.com
or whatever googlevideo.com resolves to in your area
and a dnsmasq configuration file (/etc/dnsmasq.d/97-redirect.conf), containing the following:
cname=<the domain name you want to redirect>,googlevideo.com
you can enter as many redirections as you want to, just duplicate the cname entry and change <the domain name you want to redirect>
The down side of this approach is you will have to restart pihole-FTL every time you change the configuration file.
Don't know if this a solution for what you're trying to achieve...