Can you recommend a good shared webhosting provider that you used please?
No one will host a file hosting in Shared Web Hosting, because it is shared with others customers.
Only crazy and people without knowledge will allow this happen.
You need a Dedicated Server, in last case VPS... The correct option always will be Dedicated server for such projects.
Shared Hosting you will be suspended within weeks.
I would suggest you to do the following. Keep your datas on one of the host ( A VPS ) with a minimum 5TB bandwidth( check your bandwidth usage and increase as necessary). And put your website on shared hosting. Every time customer purchase the file they can go straight to your database website and voila they can download it without giving any stress to your shared hosting provider while your VPS won’t have much load so the download will be hassle free. But the download speed will depend upon location of your customer. And when you have scaled the product you can jump to CDN and bulk buy bandwidth or divide your database to Cheap VPS location wise to have better download speed
When you will have a file hosting you need to start with the basics of the basics, then start upgrading things.
CDN is important, is where it will make things more faster. Not having dedicated server A or B or C.
CDN is a MUST in File Hosting or it will go wrong. BunnyCDN is great.
Now you will need a Offshore Hosting, because I'm sure someone will upload some DMCA content even if you comply and obey to DMCA, you can be suspended because of tons of dmca notices. Must be 1Gbps if possible 10Gbps (upgrade later)
But you are right in certain points.
-- THIS IS FOR OP and others ---
I recommend you take a look in Offshore Dedicated servers (first visit marketplace)
https://alexhost.com/dedicated-servers/https://flokinet.is/dedicated-server.phphttps://privatelayer.comhttps://www.novogara.com/10gbps-servers/
If you can't afford Dedicated server, you can use VPS but the performance won't be good as expected, good to start only.
If you can't afford VPS, then you can't do nothing. Web Hosting won't allow those things, unless you pay for dedicated web hosting which is the same of dedicated server but managed + control panel lol..