Just a correction on the PCA. The PCA came out of the PCUS before it (the Southern Presbyterian church) merged with the UPCUSA (the Northern Presbyterian church) to become again the PCUSA. The confessionalists claim the PCA was founded to be a continuing old school Presbyterian Church, continuing the stance of the PCUS conservatives in the first half of the 20th century in the PCUS. Others, those against strict confessionalism not surprisingly, say that was not so clear. The PCA has had a fight between the ever shrinking confessionalists and the broad evangelicals, which are now apparently progressives as far as the labeling, since at least the merger with the RPCES in 1982 if not since the founding in 1973. The subscription battle was lost with the forcing through of good faith subscription in 2002-4ish (I forget the year) and the stark downgrade grew at a really fast pace since then mirroring the swift changes in the country. Covid prevented this year's GA but the PCA is dealing with wokeness as far as racial issues and accepting A-side 'celebrate' gay men in the ministry. You had one or two small denominations form last year, by those giving up and leaving the PCA, one oddly ditching baptism as a confessional requirement, and one aiming to be more a mix of Old School New School, last I heard. One vocal conservative pastor's church I pay attention to as far as those visibly fighting the good fight, left for the ARP this year.
OPC has tinges of the issues in the PCA but nothing near the scale.
RPCNA is relatively serene compared to all that but has its own internal and different issues.
Both OPC and RPCNA benefit from small representative higher courts of their churches rather than the convention style PCA GA dominated by the permanent bureaucracy which is typically more in the control of the progressives.
If you are blessed to live where all three have churches, choose carefully, because all three can be like a box of chocolates.