Your seat looks like it's aimed upwards a bit - which might contribute to the twitchy - not enough weight on the front of the bike could contribute to twitchy.

But a more responsive bike may just feel twitchy to you until you get used to it.


But generally on a bike you should get it fitted and have handlebars/stem etc to fit you...

Since you saved so much, maybe you can get a professional fitting - I don't know if the orbea store offers fitting.