US CBP Preclearance at ARN was always a pipe-dream by advocates of CBP Preclearance expansion. I’m glad that pipe-dream ended up going up in smoke and down in ashes and that CBP Preclearance at ARN is unlikely to get meaningfully resurrected for quite some time (and hopefully then some more time on top of that).
CBP Preclearance at CPH would be even worse for me than at ARN, so I’m glad to see CBP Preclearance expansion get frustrated at each and every Schengen airport when this comes up.