I find it is easy to get lost in the weeds on this. I try and step back and keep it relatively simple.
If we are going to have "holy days", then what holy days should we keep? The ones that are clearly stated in the Bible, given by the Lawgiver (who is Christ)? Or should we reject every single one of them and replace the lot with ones that were invented later?
If church tradition was to keep some of the feasts as written, but replace others with another day, and there was a logic (right or wrong) behind why each of those specific changes were made that linked the old feast to a new replacement, that I could understand. It would imply continuity. However that is not what we have. Rather, church tradition is to essentially ignore every one of God's feast days, and wholesale replace them all. Only passover and pentecost have been retained in some form, and only because the church is commemorating a New Testament era event that happened to coincide with that date. There is no effort to retain or even overtly replace any of the original feast days, they are just ignored. Only sabbath has been retained, and even that has been changed.
This implies an intentional ignorance of God's instructions.
His appointed times were given for a reason. We should therefore, at a bare minimum, at least notice when they occur and consider them. Having considered them, we should give them at least as much honour as later man-made feast days, if not more. Practically, that means that if we think it is worth taking a day off work for Christmas, surely it is even more important to take a day off work for the feast of trumpets, given that was actually given to us by God himself? And surely it would be more acceptable to ignore Christmas than to ignore the feast of trumpets?