Ffmpeg causes choppy video when recording with audio

Well, my issue is simple to explain, but I tried everything to solve it without success.

I like recording gameplays, just for fun. The game I currently make recordings for is not resource heavy (it's Doom 2 through GZDoom). I'm using Lubuntu 22.04.

So, here is the command I've just used:

ffmpeg -f x11grab -draw_mouse 0 -framerate 30 -probesize 42M -video_size 1920x1080 -i :0 -f pulse -i default -c:v libvpx-vp9 -r 30 -g 90 -quality realtime -frame-parallel 1 -qmin 4 -qmax 48 -b:v 4500k -c:a libvorbis prueba.mkv

The issue is, if I record without including the audio, then the video plays smoothly after being recorded. But if I record including the audio, no matter what parameters, codecs, bitrate or anything I use, then the video is barely watchable, with lots of choppiness, and even with delay between audio and video, apparently.

SimpleScreenRecorder works fine, but sometimes there are few frames dropped and I don't like it much. OBS is very heavy for my hardware (Mac Mini 2016, Intel Core i5 1.4 GHz 4260U, Intel HD Graphics 4000, 4 GB RAM).

I also tried VAAPI, with same results as above.

And the thing is that I remember recording some years ago, with no issues at all.

I don't know what to do. Any tip or solution?