amd gpu is not optimized for apex legends. I sent several e-mails about that. they said they will work on it. whatever if you have trouble with high fps drops try to check gpu and cpu usage.
I only can help you about smooth gameplay settings. make sure ;
-use ddu for installing or removing gpu drivers.
-try to enable v-sync ( in game because freesync or v-sync in amd panel can't eliminate screen tearings)
- do not use any radeon settings except radeon chill. set to 143 fps if you have 144 hz monitor
- enable freesync
- disable windows full screen optimizations
- disable origin-ingame
-disable gamedvr on windows 10
I had same problems and still have some fps drops. make sure check your ram mhz on bios and re-install your windows 10 (clean install)
if you still have trouble wait for next driver, if you will have trouble again, go to buy nvidia graphic card for this game. I'm also waiting for new driver.