Welcome to the community!
According to the Canadian website, these are the specifications for that phone:
GSM: B2, 3, 5, 8
WCDMA: B1, 2, 4, 5, 8, 9, 19
CDMA: BC0, 1, 10
LTE-FDD: B1, 2, 3, 4, 5, 7, 8, 12, 13, 17, 18, 19, 20, 25, 26, 28, 29, 30, 66, 71
LTE-TDD: B34, 38, 39, 40, 41, 46, 48
5G NSA: N2, 5, 25, 41, 66, 71
5G SA: N41, 71, 2, 25, 66
MIMO: LTE: B2, 4, 25, 66, 41, 48; NR: N2, 66, 41, 25
Judging by those specifications, that phone should have all of the compatible bands/frequencies for 2G, '3G', and LTE. You can verify the compatible bands/frequencies here. While the phone should work on the networks, you should note that since Fido does not offer OnePlus devices, it's unlikely certain features (ie voLTE and/or Wifi-calling) will work with that device. You should also note that other versions of that device may not have the same band/frequency specifications.
You should note Fido is not currently offering 5G services (see here). They are concentrating on improving the LTE networks. As far as I am aware, none of the flanker brands are offering 5G services either.
Different levels of flanker providers offer different services. To reduce costs for customers, they must be selective in the options and services they offer. Mobile flanker brands don't get premium options like 5G, data sharing, or bundling, but their plans often offer the best balance of price and functionality (taken from here). That said, there is speculation that the first tier flanker brands could offer 5G access for a fee at some point (see here). Unfortunately, this notion is still only conjecture. No one here would know if or when this could happen. Any update on 5G access would be announced on Fido.ca.
For the moment, if you want to access 5G services, you will need to switch to one of the parent providers (ie Rogers, Bell, Telus or Videotron).
Hope this helps 😀