You don’t need a particularly fast or powerful computer to record mono or stereo. (Multi-tracking can be more demanding.)
Most “audio quality issues” are related to acoustics or the analog setup…
If you are having digital problems (glitches/gaps/dropouts) it’s “something else” interrupting the audio.
Your operating system is always multitasking, even if you are only running one application. When you record, the audio comes into a buffer (like a long pipe or holding tank) at a smooth constant rate. When the operating system gets-around to it, it reads the buffer in a quick burst and writes the data to the hard drive in a quick burst.
If the buffer doesn’t get read in time you get buffer overflow and a glitch in your audio.
There is also a playback buffer that works the opposite way. It’s written/filled in a quick burst and the audio flows-out at a smooth constant rate. It the playback buffer doesn’t get re-filled time you get buffer underflow.
A buffer is also a delay and if the buffer is too big you get more latency and it can be difficult to perform while monitoring yourself with headphones. But your Focusrite probably has “zero-latency direct-hardware” monitoring, where the monitoring doesn’t go through the computer.
If you don’t have to worry about latency there is no downside to a bigger buffer and you are less likely to get glitches.
A faster computer can help because it can finish-up the other stuff faster. But sometimes when you buy a newer-faster computer and there is more junk running in the background…
Try to minimize the number of running applications or background operations. Some people end-up temporarily turning-off Wi-Fi or their anti-virus.
If you are recording at a high sample rate (96 or 192kHz) try 44.1 or 48kHz. There is less data at lower sample rates so you are less likely to get glitches. (As you may know, CDs are 44.1kHz so it’s still high-quality.)
There are also some troubleshooting hits in the manual here.
Or there is a FREE online book about optimizing your computer for audio called Glitch Free.