Sitemap and 300 URL Restriction

I've been testing Voiceflow and so far it has been very interesting. I tried to add sitemaps to the Knowledge base but I'm running into a problem which is the error 'URLs must be less than 300'. For example one of the sitemaps we have have 10k+ URLs. How do you use the Knowledge base, I'm sure 300 URL is far too little for 90% of use cases, and manually adding 50k URLs in batches of 300 at a time doesn't sound that fun. Is the 300 URL restriction only for lower levels and in Pro version and beyond there will be no limit? Thanks!