Best Solution for writing Classical Music on Studio One

What is the best solution for anybody who uses Studio One to write Classical Music.

I composed something with Presence in Artist. But would like to upgrade the quality of the sound/synth.

I see there are options. Like Miroslav or NI also does Notion come with VST's included.

Is the Presence XT noticeably better than the Artist version also?

I use Arturia Analog Lab for Electronic and it sounds amazing. Looking for a parallel in hi-end quality.

I love Studio One so want to find a solution within that.

Thanks.