I have been using Firma F/X to pay my US and European vendors; their rates are very good, and they send ACH payments (and whatever the European equivalent is) for no fee. If a wire payment is necessary (quite rarely), it’s only $15. With ACH payments, the money is received within one business day (wire is usually same day, so not much different).
I just looked, and they also have a US division. If your customers don’t already have something set up for making foreign payments, and they’ll be using your services regularly, they could probably get set up without too much hassle. They would just need your account information.
https://firmafx.com/en-us/company/ You might want to set up a USD account to receive funds into (if you’re asking for payment in USD, obviously - I imagine you could also get a GBP account in Canada, but I’m not sure - they’re more likely to be able to pay in CAD; I think sometimes it’s difficult for American companies, though I’m not sure why). That way you can wait for favourable times to convert.
ETA: good luck with your new venture/side gig!