The 20MB file upload feature that is built-in Shopify is hard-capped at 20MB and cannot be adjusted. However, It is possible for your customer to have the ability to upload more than the 20MB file limit but it will require the use of an app from the Shopify App Store. However, you can use a third-party digital downloads app such as Kable Digital Products. I'm not sure what their file size limit is, but I tested the app by uploading a 48MB video and it had no issues.
I hope this helps! If there is anything else I can help you with, please let me know.
Avoid large files for views. If it's for download, put it on a hosting that you manage: from Dropbox to Google Drive, depending on what your needs are. Then create a custom link for your users to downoad the file. If the link is long "and ugly" use https://bitly.com/ (even a free plan) and you'll have stats on the clicks.