Run a few WP sites.
WP is obviously a very stable, backwards compatible, easy to learn plugin.
PHP is stable and easy to learn.
Tons of docs.
Tons of plugins.
Tons of hosts that overall, "just work".
Tons of developers to hire, and even those that don't specialise, a lot know it.
Staff are more familiar with WP than anything else given its massive popularity.
On the most part, free.
Realistically, is there anything equivalent with ACF, Gravity Forms, possibly WooCommerce style out there that you can actually move to? Something similar-ish rather than a headless JS completely different platform to learn with minimal overlap.
No need to jump ship overnight or hit panic stations, seems worth starting to explore what options exist. After all, competition is good for growth!