Hey there @BSVino! Welcome back to the community! Unless your game is doing anything fancy in the background, this is likely going to come down to optimization if their setup works fine otherwise. UE5 is decently heavy on it’s own for lower end systems, so if it’s user dependent I’d also take a poll of the hardware.
I’d probably first see what resource values (Memory, VRAM, CPU, etc) your users are experiencing during gameplay that might be too heavy. Then resources your game is using more than others that could be interacting with their recording setup. Here’s a solid guide to performance profiling that ties in with official documentation: