Tried it on Xbox one x and the graphics were laughable on multiplayer, and even worse on the battle royale mode thing. The game engine literally hasn't appeared to have changed for 10 years like you say!
Well I know COD gets a bit of slating on here but I bit the bullet and got it and it's very enjoyable.
MP is typical COD, as in fast and in your face... but you know what? It's fun.
I have bought a few games lately, such as Post Scriptum, which in it's own way is brilliant, very immersive. Also bought Insurgency which again is very good in it's own way, but it's that I find myself playing. It is just fun.
Blackout is probably the best BR out there, and I have sunk over 150 hours into PUBG and a fair bit of time in Fortnite. Them games are very good in their own way, but Blackout takes BR and puts it's own spin on it. It feel very smooth and polished, and is overall the most fun out of all the BR's out there imo.
Graphically the game is not great by any means. On PC in 4k it looks decent enough, some little advances other previous titles, but the graphics on COD haven't properly advanced for years! They really need a new engine. I wouldn't say it looks terrible, but not great.
Black Ops 3 was the last COD I properly played, and I sunk a lot of hours into that because MP was very fun... BO4 with the MP and Blackout will likely mean I put even more hours into this.