Firstly, a big welcome to the forums.

Your question is excellent and is often asked.

My recommendation is to go for a pak with as many RealTracks as you can comfortably afford.
The entry level Pro Pak probably won't give you the results you are seeking.

The Mega-Pak should be your base choice, or the Ultra-Pak if the budget stretches that far. (The Ultra-Pak gives you more than 2,500 RealTrack combinations)

Hope this assists in your decision making in some way.

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BIAB & RB2024 Win.(Audiophile), Sonar Platinum, Cakewalk by Bandlab, Izotope Prod.Bundle, Roland RD-1000, Synthogy Ivory, Kontakt, Focusrite 18i20, KetronSD2, NS40M Monitors, Pioneer Active Monitors, AKG K271 Studio H'phones