My experience with going to high availability has been great. I took the firm from single hardware servers installed with a single operating system and upgraded us to running hypervisors and setting those hypervisors up with high availability.
We set up high availability and multiple stages of backups. I have set up our servers in sets of three and two where the software allows High availability mode. For our citric servers we have a grouping of three that run High availability mode period with a backup off-site server in case the entire cluster goes down. We also have two Synology servers that run at high availability mode. There is only two because that is all the Synology supports the synchronization of two servers.
But do remember that high availability, like raid, is not a backup. Well all the drive discs are set up and raid and the physical servers are set up with High availability, we still need a backup. I’ve configured backups using the standard 321 rule. Have at least three copies of your data store it on at least two different Medias and have one copy off site.