Yes you can. A RC can be treated similarly to a snapshot. There have been other snapshots before and there have been snapshots after. If your device is listed as having an image in a rc-download list, you can download and install it. This has been the case for the AX23v1 with 23.05.0-rc1 already.
As for the 160MHZ question: haven't check this, since I can't use it anyways, however, there is an extensive thread on issues related to this and the chipset of the AX23v1. Not sure if it got "fixed" now and doubly not sure if this is part of the latest RC: 802.11ax worse than 802.11ac with mt76 driver?