I have a Garmin 520 and experienced the openstreetmap queue like you when putting a map together a few weeks ago. It initially said about 10 day turnaround but ended up being about 72 hours.
There's clearly still an issue then
I did try and use basecamp but struggled with it. I didn't use the velomap website to help though. Would you know if there's a step-by-step guide to use velomap & basecamp? That would help me out.