You probably won’t want to give up your public facing IPv4 addresses. If you do I’m not sure that users that are using IPv4 will be able to find you.
You should just need to add IPv6 IPs to your front end load balancers and routers and have them translate that into IPv4 on your inside network.
Some things which will have IPs if you did decide to change everything would include:
Desktops, laptops, wifi access points, switches, routers, printers, badge readers, door locks, VPN connectivity, etc.
You’ll need to know how having IPv6 only would affect people that have IPv4 only at home that will need to VPN into the office.