Coming from a client-side testing snippet, is server-side PHP rendering worth the switch?

For a while we rendered our A/B variants with a client-side snippet. The default content painted first and then swapped once the script decided which variant to show, so there was always a visible flash on the landing pages. We tried the usual anti-flicker hiding and it just traded the flash for a blank spot.

Now that there is a PHP SDK I am weighing whether resolving content server-side in our controllers is actually a better developer story, or whether I am just moving the same complexity somewhere else. Has anyone here made this move and found it genuinely better