Also, a reminder that when changing, cancelling tickets voluntarily, OTA's are allowed to charge passengers a service fee which could sometimes be really harsh.
Once I have saved about $200 on a BA ticket by booking through an OTA; although while the change fee behalf BA was something around $150, the OTA had an additional service fee of $250 for a change. I was lucky that the itinerary didn't need a change, but I've learnt my lesson to check all the policies before booking through an OTA.

Plus during COVID, many reputable OTA's had issues with refunds; constantly offering vouchers and denying refund claims, etc... so these days I also avoid booking through an OTA for this as well.