Well...yes and no
Same corporate family but that doesn't mean the servicethey provide is the same.
The other point is that Fido uses cable internet which by its very nature is subject to congestion. So before COVID, people often noticed a slow down in the late afternoon and evening when people came home from work and started to use their cable internet at home and also their cable TV services since everyone in a certain area were connected to the same pipe.
Bell casn't offer cable internet, they don't have the cable infrastructure- they offer DSL over the telephone copper pair that is limited in speed depending on the distance to the CO (switching office) or remote node or they offer fiber if they installed the fiber infrastructure in your area. Fiber can deliver a much higher bandwidth than cable so for congestion to happen you need a lot more users at the same time and fiber can be configured to avoid that.
In your case the fiber connection terminates in your building, thus FTT"N", then the final connection is via the telephone pair.
Each telephone pair only services one apartment, so you are not sharing that part of the connection with anyone and because the distance from the fiber node to your apartment is short, you can get pretty good speeds - and most important -the speeds will be consistent.
Sorry, I'm writing a lot more than planned.
Just in general, a VPN connection usually slows speed down a bit but it should still be fully adequate.
You can check that by running a speed test with and without VPN - I usually use Ookla for my speed test