Many Asus home routers advertise compatibility with and/or run OpenWRT internally, so yes to a certain reading.

Here's a random example I found:

https://www.asus.com/networking-iot-servers/modem-routers/al... | https://web.archive.org/web/20250704161852/https://www.asus....

Installing a custom firmware on a router does not count as 'off-the-shelf' imo.

I’m not speaking hypothetically, as I have used VLANs on native stock Asus firmware.

https://www.asus.com/us/support/faq/1049415/