Hey, I had the same issue after an update – keyboard clicks super quiet in most apps except Apple's own.
Try this:Go to Settings > Sounds & Haptics > Keyboard Clicks – make sure it's turned ON and slide the volume ringer all the way up.
Then, open Settings > Accessibility > Touch > Haptics – set it to "Always On" (sometimes "Auto" makes it too weak).
Also check if Low Power Mode is on – turn it off, as it lowers haptic/sound feedback.
After that, force quit the social apps and reopen. Worked for most people with this exact problem.
Let me know if it helps!