Easiest Guest Wireless Playback Option

Objective - I want guests to be able to easily wirelessly play audio on my main system from their devices. Primarily interested in the playback of live recordings (vs. streaming their service), but capability for both would be ideal.

Current Set-Up - Roon -> WiFi -> RPi4 (Raspian) -> USB -> Pro-Ject S2 DAC/Pre -> Onkyo M-5160 -> Vandersteen Model 1s

Thanks in advance!

For anyone interested in offering guests a bluetooth and/or 3.5mm playback link to their system, I found two options for a bluetooth receiver that can output to the XLR jacks on my Pro-Ject S2 DAC/Pre-amp.

DENON DN-200BR - https://www.amazon.com/dp/B015HYSG5E/ref=psdc_14269301_t1_B07WG9JB8D

Kali Audio MV-BT - https://www.amazon.com/Kali-Audio-MV-BT-Professional-Bluetooth/dp/B07WG9JB8D/ref=cm_cr_arp_d_product_top?ie=UTF8