FPS dropped in RDR 2 after changing the old monitor to a new one. (Red Dead Redemption 2)

I decided to contact here, as the FPS dropped with the new monitor in RDR 2 - everything is fine in other games.

There used to be a monitor - Samsung SyncMaster 760BF, 17-inch with a resolution of 1280x1024.
I bought a new monitor to replace the old one, since the screen on Samsung has already started to flicker a little, and in general I wanted a newer and better monitor.
Now the monitor is Dell SE2417HGX 23.6 ", so now I play at a resolution of 1920x1080.

Hardware in the PC:
i3-8100
1050ti ASUS 4gb
16gb DDR4 Samsung
Hard drives do not matter, I think, but I'll write just in case.
WD Blue 1TB HDD (5400 rpm )
WD My Passport 1TB HDD (external, connected via USB, this drive has RDR 2 installed)

As a result, I drove into many games that I had played before, but on a new monitor, everything is fine. And I decided to go to my favorite RDR 2, set everything up for a new monitor, absolutely everything, and instead of 55-60 FPS I got 20-25.
I tried to shamanize with the graphics settings, nothing came of it, the same 20-25 FPS. I do not know what the problem is, I hope they will help me here. Thanks in advance for your advice and help.