I can get a solid 60 (when capped with 60fps, goes to 90 frequently if uncapped) in a private match solo either as a fire team member or a Predator.
My system is as follows:
CPU: [ Intel I7 6700K Overclocked 4.6GHz,]
GPU [EVGA GeForce GTX 1080 Ti SC Black Edition GAMING, 11G-P4-6393-KR, 11GB GDDR5X, iCX Cooler & LED]
RAM [16GB 3000Mhz DDR4 Corsair Vengeance Heatspreader @ 4000MHZ]
MoBo [Gigabyte Z170X-Gaming 5]
OS [64-bit Windows 10 Pro]
SCREEN: Acer Predator X34P 34 Inch WQHD Curved 1900R ultrawide QHD (3440 x 1440) Gaming Monitor]]
When I play multiplayer the frames can dip to 40’s (all settings). This happens more frequently with PS4 players on the Team. It’s to do with the servers, and this is why PS4 players are seeing the same dips.
Anyone claiming excellent solid performance (even with a 2080TI) without dips I’d be sceptical of unless they can record a full game showing a frame monitor. Even streamers have those frame dips from time to time and the machines they have are godly.
TLDR: you won’t be able to solve the performance as it’s not down to your machine, also posting on this forum won’t garner you a great deal of help sadly as there’s a lot of aggressive defence for the game from younger players who feel this is the thing to do for a game they enjoy, and they will zealously refute any/all slights against the game.