CanaKit’s Pi 4 Starter PRO is the most-trodden path in cabinet building: Pi 4 with 4GB RAM, a pre-loaded 32GB card, a fan case, heat sinks and CanaKit’s filtered 3.5A supply with an on/off switch. Pi 4 emulation is the most mature and best-documented option there is.
Everything needed is in the box, and every problem you might hit has been solved publicly already.