The Witcher 4 Stuck In Development Hell Due To Unreal Engine 5, Says KCD2 Director

Only Respawn at EA uses UE, (coming from Source engine which still powers Apex), others still use Frostbite. Next BF will be on Frostbite, Dragon Age Veilguard was on Frostbite, Dead Space Remake was on Frostbite, NFS is still on Frostbite etc, etc.
Other devs who also abandoned their own good engines are eidos,crystal dynamics, IOI and slowly likely square enix as well.
As for proprietary engine which is still kicking around, you forgot Remedy’s Northlight, Rockstar’s RAGE, Avalanche’s Apex, Monolith’s Lithtech, ubisoft’s AnvilNext(Snowdrop was created by UbisoftMassive for their own Division games, whereas other ubi studios used other proprietary engines like mainly Anvil, now for the first time, FarCry devs will abandon their own Duniya engine and will use Snowdrop for the next Farcry).
And of course there’s CryEngine, powering Kingdom Deliverance 2 and Crysis 4 as well as Unity powering stunning upcoming games like No Rest for the Wicked
~fin~