The lack of vat synchronisation is not a "teething" issue.
Higher level transactions will smooth out in time, however, consumer level transactions are stuffed, and will be forever.
There are costs involved with vat collection. Royal mail has been overcharging for them for years, but there are still costs regardless.
To say "we have been doing it fine elsewhere for years" neglects the minimum £8 (+vat) charge that RM etc have been applying to non EU transactions for years.
Again, say goodbye to buying without additional costs, but, way way more importantly, all those firms serving EU consumers directly now have additional costs implied.
If those firms are specialist low volume firms, legitimately working under the UK vat registration threshold, the situation becomes even worse, as, not only are their products suddenly 20% more expensive to EU customers, their customers will also be hit with clearance fees.
I would imagine that there would be a number of specialist wood workers in this class.
I am in this class with specialist metal work.
I know someone who builds custom wood burners. He has (well had) built up a good EU presence.
These are not teething issues. The lack of vat synchronisation isn't about people learning how to fill in forms better. It is, in a lot of cases, a terminal barrier to specialist low volume direct to consumer trades.