If cost is no issue, I don’t see any issue with importing 42,000 items. Just contact webflow support here support@webflow.com to purchase 32,000 extra CMS item limit for your business hosting.
IIRC 1000 = $10/mo, so 320 + 35 = USD$355 per month, which brings us to USD$4,260 per year.
A text file containing 42k records with five fields would be around 12MB, which isn’t that large at all, considering webflow handles video uploads quite quickly.