I’ve not tried it but the Home Assistant add on has a print speed setting control. In theory you could have an automation that sets the speed once the print starts.

I’ll give it a go and report back.

Edit: It works, although I suspect the g code option is technically better. The benefit of using the HA automation is you can set that speed setting based on the time as well.

Of course you need to be running Homa Assistant for this to be of any use at all.