Honestly, buying that Canon RF 85mm F2 Macro IS STM is going to save your bank account and honestly, nobody at the wedding is gonna pixel peep your bokeh that hard. People obsess over the Canon RF 85mm F1.2 L USM like their life depends on it, but for a wedding, the weight and cost just dont add up. The f/2 lens is sharp enough, and having image stabilization is actually a lifesaver when you're shooting indoor receptions with lower light and dont want to crank your ISO to the moon. Just be careful with the autofocus speed on the cheaper RF glass; it isnt as snappy as the L-series, so make sure you practice hitting your focus on moving subjects before the big day. If you really feel like you need more reach or a different look, look into a used Sigma 85mm F1.4 DG HSM Art for Canon EF with the mount adapter. You can find them for way less than the RF native lenses, and the quality is legendary. Dont stress about the gear too much though. Your clients care about the moments, not your lens specs. Just make sure you have enough batteries and some decent memory cards, and you will be fine.

Jumping in here. Regarding what #2 said about looking beyond native glass, have you considered the Canon EF 85mm f/1.8 USM? It is super cheap used and fits perfectly with the adapter. Or maybe the Tamron SP 85mm f/1.8 Di VC USD? It has stabilization which is clutch for dim receptions. Are you planning to rent or buy? I've used both and they perform solid for the price. TL;DR: Don't stress the L-series for weddings.

Coming back to this, I would politely suggest looking beyond just the native RF mount options if you are constrained by a budget. While the f/2 is fine for general use, wedding environments often have inconsistent lighting where the optical performance of third-party glass can actually outperform entry-level native lenses in terms of chromatic aberration control and sharpness wide open. You might want to consider the Sigma 85mm F1.4 DG DN Art Lens for Canon RF if you can stretch your budget slightly used, or look at adapting the Sigma 85mm F1.4 DG HSM Art for Canon EF with the standard EF-EOS R mount adapter. Be careful with the RF 85mm f/2 autofocus speed during high-pressure events, as the stepping motor can be a bit sluggish compared to ring-type USM motors when tracking moving subjects at a wedding. Here are a few technical trade-offs to keep in mind:

• The RF 85mm f/2 exhibits significant focus breathing, which might complicate your framing if you need to perform quick focus pulls during the ceremony.
• Adapting older glass often provides better micro-contrast than entry-level RF primes, provided your adapter is fully compatible.
• Make sure to update your R6 firmware, as it improves Eye-AF tracking stability with adapted third-party lenses significantly. I would suggest testing your specific configuration for at least a few hours before the event. Don't underestimate the utility of a sharp lens even if the bokeh isn't quite as creamy as the f/1.2 L series.