1074 Column length too big for column 'category_description' (max = 16383); use BLOB or TEXT instead
1074 Column length too big for column 'mf_category_desc' (max = 16383); use BLOB or TEXT instead
Those are the fields in _virtuemart_categories_en_gb and _virtuemart_manufacturercategories_en_gb, who when looking at the structure (in t.ex. phpMyAdmin) are set to varchar(19000), and they needs to be edited and change to TEXT without a length. Same for other en-gb tables, except _virtuemart_vendors_en_gb where the length set for the fields vendor_letter_header_html and vendor_letter_footer_html needs to be reduced to 6500 (if I recall correctly). If there is more language tables in use, they might need a edit too.
OK, I stand corrected there. Thank you.
I think I was up against those issues on J! 4 about 3 - 4 weeks ago but my recall has grown a little fuzzy. I still found other problems with VM 4.0.2 (stable, compatible J4), 4.0.4 (stable, compatible J3/J4), 4.0.6 (stable, compatible J3/J4) though that made them unusable for live production sites taking actual orders.
After rolling back MariaDB to MYSQL, trying different versions of PHP while applying a number of other tweaks at a server level, I then started with just core VM & J! installations... Bingo.
The last place I thought to look was at VM 4.0.2 (stable, compatible J4), 4.0.4 (stable, compatible J3/J4), 4.0.6 (stable, compatible J3/J4) because they were and still are being presented as stable and compatible...