Question about betting exchange

I have a question before deciding to open a pro account that gives access to betting exchanges.
I can access Smarkets and Betfair from Sweden.
Betdaq and Matchbook I can access using a broker who takes a 50 Euro fee (real person account).
And a 5 Euro fee for VPN.

Now to my question, can I get the required amount of betting opportunities to get a return on investment just using betting exchanges - if not - can I compensate with a larger bank and unit size?

Thanks for the help